Undertale Meta And Other Theories - TV Tropes (2024)

WMGs as well as Theories surrounding Meta as well as other Theories not grouped with anything else for Undertale.

Undertale takes place in the Homestuck multiverse.

When a SBURB session is won, it seems the newly created universe has a "main" planet created for the victorious players to rule over, and which hosts the SBURB session of their universe. But at the end of Homestuck, the kids brought their planet with them and are ruling over that. If that's the case, where is the planet created by SBURB? Maybe it's the Undertale planet? I feel like there's some interesting points.

• Annoying Dog can do a lot things that goes unexplainable even to monsters, and is implied to be very powerful. First Guardians are space warping guardians of a planet that get their powers off of the Green Sun, and are completely white. Going further, two out of three guardians have been animals with their names a referance to science (Gcat and Becquerel, which Annoying Dog fits among if you name it "Radiation", wink).
• Humans (atleast Frisk) have inventories. This immediately reminds me of Sylladexes, which are basically inventory systems every character has in Homestuck. While this would be a stupid comparison if it was to any other game, since Undertale has Saving , LV and Stats as actual canon things, there's no reason to believe that the inventory system is not a canon thing.
• Alternia had Lusi, which were monsters that took care of troll kids. While these creatures are much more like monsters than, well, monsters of Undertale, looking at their wildly varying shapes, sizes and powers, as well as the fact that they co-exist alongside another sapient species on their planet (Trolls/Lusi, Humans/Monsters), it is possible to draw connections inbetween these creatures and monsters of Undertale.
• Soul types (this might be stretching it) might have a connection with Aspects of Homestuck. As far as I've seen, Determination seems to be connected to Hope and Time, but since that is the only Soul type we see in action (Not counting bosses changing your soul due to the fact that's probably different than purely having a soul of that color), I can't say any more on that surely. Some speculation though is Perseverence being connected to Doom, Patience being connected to Mind, and Kindness being connected to Life.
• Or maybe I'm overthinking this and Toby was just highly influenced by Homestuck due to making music for it, being friends with its creator and presumably reading it a lot. Still, some nice fan content material.
• These points are probably just evidence that Homestuck has influenced Undertale. The planet ruled by the kids is Earth, crippled with Liberty Statue, where lives Carapacian and where is located Can Town. This is too close to Undertale. Toby Dog is powerful because he is the avatar of Toby,not because he is a lusus, he doesn’t teleport in screen or emit green flahs. Inventory is extremely current in the videogame, and this one is not complicated to use, nor does it allow to carry extra-large things. Monsters are very common in all videogames and absolutely don't need to be Lusus. Anyway humans aren’t necessarily trolls, and Lusus aren’t their parents. They are 7 soul types, not twelve - anything can have a little ressemblance of aspects.

The Dreemurs are Luck Dragons.

Think about it. The white fur, the fangs; heck, even the floppy ears are reminiscent of a luck dragon.

Toby Fox may have gotten inspiration from FFXIII.

Vanille is either Sans or Alphys, with both having dark pasts. If Vanille is Alphys, Undyne is definitely Fang, with her battle skill, spear-wielding and...well... love?

SOUL is also an acronym

SOUL is always capitalized in the same manner as EXP and LOVE. Maybe it stands for Source Of Unlimited Love?

• Or Source Of Unlimited LOVE, in the No Mercy path.
  • Alternatively just like LOVE ain't love and E Xecution Points ain't experience points, it is very likely that a SOUL isn't a soul, but something different alltogether. I recommend reading this, which goes into detail what a SOUL actually is. What is the SOUL? - A theory and headcanon about the nature of SOULs, as well how they correlate with Chara and Asriel Also here different abbreviations for SOUL.
  • Source Of Unconditional Love or if you are a nerd Spiritual cOnnection to Unconditional Love.

GOLD, too, is an acronym.

Since you typically get GOLD by sparing monsters, maybe it stands for Graceful Optimism and Likable Demeanor.

Each SOUL can manipulate its own repsective aspect, but most have yet to use it to its full potential.

• The Red SOUL, whose trait is DETERMINATION, is able to control time, SAVES and LOADS, and even refusing in the battle against Asriel, the SOUL has grown so powerful and determined that it can essentially rewind time from the brink of death or even at death instantly, without the need for savepoints.
• The Purple SOUL, Perseverance, is able to control space. The battle against Muffet locks your soul into three lines on the grid, but movement between these three lines is also much faster than how a red SOUL moves freely. In addition to this, the only other time a Purple attack is used is in the battle against Sans in the form of KR poisoning. We also know that Sans has some sort of teleportation ability, which was implied throughout the Pacifist and Neutral routes, but he outright does in the No Mercy/Genocide route. Teleportation would make sense to a person who can manipulate space. This also explains why he has knowledge of the anomaly (besides his possible study into quantum physics), but no memory of past events after the player LOADS.
• The Green SOUL, Kindness, can possibly control energy, more specifically, the concept of energy in non-modern metaphysics. The ability to heal and create a shield are two common basic applications for energy. Despite this healing, the SOUL can not resurrect dead beings.
• The Yellow SOUL, Justice, can manipulate magic, becoming yellow inverts the heart which makes it similar to a Boss Monster's SOUL, and monsters can use magic. This is also evidenced by the fact that among all the modes the soul can take, only this color can "attack." I got this idea from a comment on the wiki.
• The Cyan SOUL, Patience, can control waves, not just waves in liquid, but waves in general, in physics. This is why not moving from cyan attacks can cause you to take no damage, as you are letting the wave pass through you.
• The Orange SOUL, Bravery, in contrast, controls particles, which is why moving through them does not damage you.
• I am unsure what the Blue SOUL manipulates, but I'm inclined to say causality for some reason. Perhaps it controls gravity, as with Jump Mode.

The Souls' colors are based off the most dominant Chakra of the individual, each color being the most pronounced aspect

• The Root (Red); is associated with Self-preservation and being grounded
• The Sacral (Orange); is associated with Intimacy and Emotion
• The Solar Plexus (Yellow); is associated with Energy and Vitality
• The Heart (Green); is associated with Hope and Compassion
• The Throat (Light Blue); is associated with Communication and Creativity
• The Third Eye (Dark Blue); is associated with Insight and Intuition
• The Crown (Purple); is associated with Enlightenment

A fusion of the two previous WMGs: that the SOULs' colors are based on the seven Chakras, as well as being tied to a given cosmological concept

By a "cosmological concept", it is meant some aspect of the universe that is so grand and broad, that it couldn't be grander and broader. Think of the six infinity stones from the MCU. They tie to: space, time, mind, soul, reality and power. For this WMG, four tie to something physical: space (cyan), time (green), electromagnetism (yellow), and thermodynamics (orange), and three tie to magic itself (as in, these are magic-related magical powers - metamagic): magical constructs (blue), magical power (purple), and magical nullification (red). As can be seen, several of these precisely match the respective infinity stones. But that is just a coincidence. Anyways, here are the respective colors:

• Red: Is not based on determination, as there exists compelling evidence in the game (compiled by nochocolate on Tumblr) that determination is actually yellow. In actuality, red is "being yourself", as evidenced by the Ball Game in the snowy part of the game. However, this is rather whimsical, so the author of this particular theory got the idea that "being yourself" (or "ipseity"), when translated to some kind of magical power, could be the ability to deprive other types of magic of their strength, to 'reduce' them to nothing but themselves. This would for example explain why Asgore's spear (which is red, despite battle sprites usually being all-white) can destroy your MERCY option - as it's capable of overpowering even determination itself. In other words, the cosmological aspect that red represents is the overarching authority over other types of magic (or nullification if you prefer). What then ties this unique power to the red chakra is the fact that it's the Chakra of self-preservation and fear. Wouldn't you fear yourself if you had the unparalleled ability to instantly destroy any and all magic that might stand in your way, even a determination-based one?
• Orange: This type of magic hurts you in the game only if you stay still. However, this is a bit difficult to explain using motion due to relativity of perspective, so an idea was born that this could instead represent some sort of fiery 'fluidum' that stacks up if things stay still and inflicts damage, and disperses otherwise. In other words, it could be a physical manifestation of thermodynamic... something. What then connects this to the orange Chakra is the alternative meaning of bravery: passion. Since the orange Chakra represents passion, and orange attacks are tied to the virtue of bravery in the game, the connection checks out.
• Yellow: Is speculated to be connected to determination. Alphys built a device in the game that uses the SOUL itself to shoot bullets. Since all human SOULs have the power of determination in common and other possible sources of power are only speculative, this is the best candidate for explaining what exactly powered her device. Yellow also represents justice. While a massive leap in logic, it can be said that true justice, in the worse case example where a suspect is unwilling to confess to a secret, can only be achieved by mind reading. Furthermore, Undertale hinted a few times at the concept of an "essence" (mainly the books in the librarby of Snowdin did). Since Flowey was born from a determination-activated essence (which came from his dust after he died on the bed of Golden Flowers in Asgore's garden) and since we also know that he lacked feelings but all of his memories were intact (ergo he still thought of himself as Asriel), it can be said that yellow magic, which, as mentioned above, could already be connected to determination and mind, also governs essences. Lastly, since determination is often said to be an aspect of physical matter (as without physical matter, a living being cannot accept determination, as discovered by Alphys), it would also mean that yellow magic is connected to the physical world. This finally establishes the cosmological connection: electromagnetism (which is both physical and mind related - think electrochemical signals). And as for the chakric connection, we are talking about the solar plexus: energy, vitality, mind, ego, all that jazz. It all checks out. Truly, the wildest mass guess in the west. (Def not a pun about the yellow kid.)
• Green: Since it is very difficult to connect this one to any plausible overarching cosmological concept under the assumption that it is healing-related, it can instead be thought of as simply time-reversed magic. In other words, green governs time/time reversal. And as for the shields that Undyne gives you and the green SOUL mode preventing you from fleeing, well, something has to prevent space and time from imploding when you move a localized chunk of it back in time. In other words, an isolation field is required. This theory has its holes, but that's precisely why it's a WMG. And as for the chakric connection, it's practically self-explanatory: healing - kindness - heart Chakra.
• Cyan: Pretty much everyone who ever thought about this has figured that cyan is space/spacetime/portal-related, so I will cut this one short. Cyan detects movement; movement = some relativistic mumbo jumbo = spacetime (but excluding backwards time travel; that's green magic's domain). Next, while the cyan Chakra is associated with the throat, which represents communication, some sources also ascribe it knowledge and philosophy (particularly doctor Malavika Suresh), which would agree with it being all about "patience", as patience is a virtue of logic and academia.
• Blue: Most people think that this one is gravity-related, as blue magic does change your gravity in game. But blue also represents integrity, which makes little sense together. However, if we assume that blue actually manipulates any magical construct and/or that all magical constructs which bear a concrete shape are woven from it (e.g. SOULs, magical attacks, magical body parts), then "integrity" can also mean structural stability. Ergo, blue attacks aren't gravity-related, they are simply the result of moving the said magical constructs using telekinesis. Hence why the cosmological theme for blue magic is "magical constructs". And integrity itself connects to the third eye Chakra simply by that fact that this Chakra essentially represents wisdom. Integrity could be thought of as one of many virtues related to wisdom.
• Purple: Purple magic locks you into predefined paths (Muffet) and also inflicts long-lasting poison (Sans's KR). The latter could be attributed to some sort of spell permanence / attack repetition (which would agree with the associated virtue, perseverance), while the former could be tied to this by noting that purple magic doesn't hurt you. If it truly is a simple spell modifier that multiplies attacks, then 0 times anything is still 0. In other words, no white magic to tie to and purple magic won't do any harm. So the cosmological concept that purple magic represents is augmentation of magical power, which is a nice parallel to red magic, which represents the exact opposite. And all this relates to the crown Chakra by the fact that it represents spirituality/religiousness. And in a way, religion does give one an inexplicable source of internal power, just like purple magic itself.

The original author of this massive WMG is Tsskyx, who has come up with it independently, even before discovering this particular website and the ideas already shared on it.

Frisk is the only one to almost completely master their aspect.

Because, despite the previous WMG, Frisk, has a Red SOUL. The other SOULS, while they had the potential to be powerful, died before they could get better at their abilities. The farthest anyone made it was the Yellow SOUL with their ability to manipulate magic, and the Green SOUL which enabled them to heal themselves, but none of the previous SOULS had the ability to resurrect themselves from death as Frisk's Red SOUL does.

Hey, someone had to propose a crossover idea sometime. Chara is actually the new incarnation/host of the Demon King Odio.

After defeating Pure Odio, Oersted's final form as the Demon King and final boss of Live-A-Live, he declares before he dies and fades into nothingness for good that as long as hate exists, anyone can become a demon. Cut to a time unbeforeseen in the game, either between any of the other timeframes or in a new universe entirely that spawned after the end of the old one at some unspecified point in time, and the Demon King itself has survived to the present day as a nebulous presence, and eventually sensed Chara's hatred towards humanity and possessed them, thus leading to them hatching their big plan and setting the plot of the game into motion. The Demon King couldn't manifest it's powers for a time, and needed more than simply Chara's (admittedly horrifyingly vast) hatred to regain it's former strength after such a long period of inactivity, leading to Chara's planned death; if the player goes for the No Mercy Ending, Odio's power returns greater than before, and it came back with a massive upspike in savvy to boot after realizing the power of SAVE.

• Thankfully, it's only in the No Mercy ending that Chara/Odio wins; the final bosses of each route can be taken as Odio evolving into its Pure Odio form, as it did once before back in Live-A-Live, but each being different due to the circ*mstances. In Neutral, Omega Flowey represents Odio using the flower form itself to manifest, and is possibly the most raw of the three in terms of appearance and sheer malicious behavior during the fight. In the True Pacifist ending, Flowey manages to reclaim his original form as Asriel, but Chara and Odio are having none of that and again possess him, this time allowing the Demon King even greater power than before when combining the power of all the souls in Asriel's body with all the hatred the Demon King has managed to feed on from Chara's soul and Flowey's hate. This is the manifestation of Odio that most closely resembles the original Pure Odio as well as the battle that ends in the most similar way, and when Frisk finally manages to save all the souls Asriel has trapped, as well as Asriel himself, Chara's soul is destroyed at last and Odio no longer has anything to anchor to, banishing the beast from this world until it has fed on a sufficient amount of hatred to again rise. However, the No Mercy Ending is, as said before, the Demon King Odio's victory; roughly equivalent to the Armageddon ending of Live-A-Live with a bit of the ending when one completes Odio's final chapter thrown in. Chara has successfully manipulated Frisk into becoming the new host, and thus Odio takes hold of the body of the Fallen Child reborn, and with all its power, the Demon King destroys the entire universe of your game, with plans to move on to another Undertale universe to feed off the hatred there and eventually destroy it, too.
• Alternatively, with the completion of No Mercy, you created under your guidance the enity known as Perfectio, the king of ruin.

MEGALOVANIA is not Sans' boss theme, but yours/the Fallen Child's.

Not necessarily my idea, but I figured I should put it here anyway. Sans already has a theme—'Song That Might Play When You Fight Sans'. And it's not like the other Dummied Out songs like Gaster's Theme, Happy Town, Meat Factory, or Trouble Dingle, which are just repetitive, simple loops of music. In every medium that MEGALOVANIA has appeared in, the scene always had a common theme in it: a character (two out of three times the 'protagonist') killing someone in cold blood and not caring, despite the fact that they could've turned around and chose a different path.

''You feel a little like this situation could have been avoided. Oh well. You really did have a choice...you could have stopped altogether...''

In most video games you're saving your world from the brink of destruction, however in a No Mercy route it's the other way around and instead it's Sans that's fighting to save what's left of his world. He even fights in many ways someone playing a video game would: big, flashy attacks, dodging attacks (which, even in this game, only the player could do), and even stalling in his turn to buy time. You're the final boss of Sans' game, and MEGALOVANIA is your battle theme.

• Basically, you're not fighting Sans. Sans is fighting YOU.
• In the same way, Hopes and Dreams is Frisk's theme rather than Asriel's.
  • It might actually be SAVE the world, considering the context.
• To further support this point, all of the other songs specifically related to Sans — "sans.", "It's Raining Somewhere Else", and "Song That Might Play [...]" share a common riff, but "MEGALOVANIA" is an unrelated track.

Adding on to the previous one, if Sans had decided to fight you in any other path...

That's when you would have heard "Song That Might Play When You Fight Sans". That is his normal boss music, but you never heard it since he promised Toriel he wouldn't fight you.

And combining the previous two with entries higher up on the page...

Given the theme of being Dummied Out surrounding W.D. Gaster, "Song That Might Play When You Fight Sans" could itself be Dummied Out because of Gaster's absence.

• It's possible that, if Gaster were around to be the "judge" as suggested in previous entries, he might have sent Sans in his stead given their connection and had him test the hero's determination and dedication to showing mercy with an easier form of Sans' No Mercy boss fight. In this case, the dummied out song would have played. Because Sans doesn't fight you unless he absolutely feels like he has to — i.e. a No Mercy run, where MEGALOVANIA plays instead — and he didn't have the push to test you, it never does.

Humans and monsters have different battle interfaces

If two humans were to fight each other, then it'd play out like a typical RPG battle, the battle's outcome being determined by raw stats, while two monsters fighting each other would play out more like your typical bullet hell, with both sides throwing and dodging bullet patterns. After all, the only kind of battle we see all game is human vs monster.

The battle system works depending on how alert you are

That's why Flowey and Sans are the only characters to have used an unavoidable attack, as at the beginning of the game you weren't expecting Flowey, who just tricked you/had been using easy to avoid attacks up until then, to suddenly pull out an attack like that, it also explains why Sans can only do an unavoidable attack if you spare him, as sparing him means you let your guard down and leave yourself wide open, It'd also explain why you get an outline for a number of Omega Flowey's attacks and why all of Sans's attacks are avoidable, as you're alert during those fights. It'd also explain why Omega Flowey can trap you in an unavoidable attack at the end of the fight; the shock of seeing your efforts being negated made you incapable of being alert.

Actually, the best ending is the normal ending. With the barrier still standing.

The barrier is actually there to protect the monsters. A human can't enter the barrier without a monster's soul, and there's no other monster in the outside world. The only way human can enter is by falling a hole, which would probably discourage many.

• It was stated in game that anyone could enter through the barrier, it's leaving that requires a human and monster soul. As a result, this wouldn't be an effective method of protection.
• The game implied that Humans Are the Real Monsters.
  • The first Fallen Child might be horrible, yes, but they are still a child. What actually caused them to hate humanity so much?
  • In the True Pacifist route, Frisk is asked why would they climbed the mountain in the first place, if it was rumored people would never returned from the mountain. It isn't far off to guess that Frisk might have fallen down the hole on purpose.
  • Bonus point in the end if Frisk stayed with Toriel instead of family or their caretaker. Alternatively, Frisk said they had places to go. Why mention places, plural, instead of home?
• While most monsters are peaceful and mean well, that doesn't mean they can't (accidentally) harm humans. Anyone who played pacifist route knew this. How many incidents would happen now that the monsters had moved above the surface? Eventually it would end in another war.
• Either there would be some good people accidentally harmed by monsters...or, alternatively, there would be some other people who would purposefully seek this 'random encounter' for free EXP. The No Mercy route only took one kid to do it. Now monsters would encounter the ENTIRE human race.
  • If there were another war against humans, monsters can't really expect to win. Not without truly becoming 'monsters' like what Flowey did...
• Only humans can SAVE (and reset). It is unknown if ALL humans can do it, but it doesn't seem to be a rare ability. What's stopping some children from killing some monsters and do it again? And again. And again. And the monsters wouldn't even be aware of it.
  • Well, judging by how the protagonist "usurps" SAVING from Flowey, there are probably substantial limitations to it - only the Most Determined Person in a given place can do it, say.
• Even if there were no wars between humans and monsters, it's possible there are still wars between humans.
• Tl, dr; The True Pacifist ending might not be the happiest ending. It is also lampshaded by Asriel that the world above isn't as kind as the underground.
• This is all Jossed, for what it's worth - Toby's said that the True Ending is meant to be taken at face value, and while we might expect some Fantastic Racism, anything beyond that would be dipping into AU territory.

The consequences of the final Pacifist choice.

Choice without consequence is boring, so it's guessing time. Staying with Goatmom is obviously the most heartwarming and most detailed of the endings, as well as the first option. Not to mention pretty much everyone's favorite pick. But is it really the best choice? There are actually a few potential hints that this may not be the case. First of all, the turtle shopkeeper. If you talk to him during the final walk, he informs you that even if you are adopted into the Dremurr family that they will surely outlive you. While it is sad that Toriel will remain lonely if you leave, eventually you are dooming her to once again bury her adopted child. Second the silver key easter egg. The room which it unlocks doesn't contain too much until the final walk of the True Pacifist route. During this segment, the room will contain a photo of Frisk and all of their Underground friends. This is implied to be the same photo you see at the end if you choose not to stay with Toriel. Well, Sans obviously has deep knowledge of all the timelines, but why would he leave that photo there at the very end? He could very well be trying once again to guide you in the right direction. Third, Frisk DOES have a home. It is mentioned as one of the choices to leave the ruins very early in the game. So, the question is why did they leave? The game gives no answer. It could have been terrible circ*mstances, abuse, etc. Or perhaps even entirely selfish reasons. Either way it was likely not a happy reason. Whatever the case, this may very well be what Frisk was referring to when if they say "I have places to go." There still may be business they need to settle or come to terms with, and by staying with Goatmom they instead decide that it is better to just run away from them.

• It's implied that the anyone could have ability to SAVE if they are determined enough. Unless there were an equivalent of Time Police or something that watched the timeline(s), there would be plenty of timeloops in the human worlds.
• Some good people might use the ability to reset to save the world. Some others...what stops a crazy serial killer or a rapist from committing his crime several times, and repeating again?
  • See the above point though, the fact that Flowey loses the power when the Child gains it implies that only one person can have the power to SAVE and LOAD at any time, I don't think they'd have to worry about your average Joe getting a hold of that kind of power. And all this is even disregarding the fact that the ability to SAVE and LOAD may not even exist in the overworld and might have been a result of whatever happened to Gaster.

The barrier acted as a time barrier as well

The barrier is allowing the underworld to have a linear timeline, no matter how many times a reset happened in the outside world.

This explained why you can only reset the time back to when Frisk falls. Given how determined Frisk was, it is difficult to believe they didn't have a SAVE point back before they fall, it is just simply NOT accessible to them. If they could, they would simply just RESET the time back before they fall.

In No Mercy, Sans's dialogue referred to you as an anomaly in time. Why it must be you when there could be any other humans above that repeated the timeline? It's just you're the only one that can be observed changing the timeline in underground, as the human world had their own timelines.

• This would also explain why Asriel doesn't seem to be too worried about turning back into Flowey as long as he's stuck in the Underground, even if he can save and reload again, assuming he can only do it as far back as when Frisk lost the power upon leaving the Underground, he can't reset again, only YOU can.

The status of the relationship between Asgore and Toriel?

Asriel Dreemurr was revealed to be the child of Asgore and Toriel. The two have since separated. One of the anagrams of Asriel's full name is "Serial Murderer", which references him taking all the monsters' souls for his fight against the player. But another anagram for the name is "Rulers Remarried". This could also be meaningful. Does this mean Asgore and Toriel eventually reconcile? Or does it mean they find other relationships? Of course, this could also be overthinking things. We may never know.

• Sorry, but Asriel Dreemurr is one R short of being an anagram of "rulers remarried". Nice thought, though! That does, however, mean it's an anagram of "rulers e-married", which can mean only one thing. Some time after moving to the surface, both Toriel and Asgore turn to internet dating. And of course they unwittingly pair up with one another. And then they agree to meet up and find out who they were getting along so excellently with online. And since anagrams are the most powerful force in the universe, they obviously reconcile and get back together. Obviously.

In addition to not having blood, most monsters don't have bones either

Which would make Papyrus correct in his theory that humans descended from skeletons!

Why Papyrus and Dr. Alphys are OK with dating a kid.

It's kind of obvious monsters don't work the same way that humans do, but it goes deeper than the magic and appearances. My theory is that monsters don't gauge age the same way humans do. Instead of looking at how old they are, they look at how developed their soul is. Boss monsters only age when their children do, by giving bits of their souls to them. This makes it seem as if the child doesn't quite have a fully developed soul, and by monster standards, isn't mature.

Frisk, however, is a human with a fully developed soul, capable of fighting and such even at a young age. Monsters are more or less nothing without their magic, while humans are very much a physical race. Monsters can't really tell the age of someone by sheer looks, considering how just plain odd they can look.

Thus, Dr Alphys and Papyrus aren't creeps, they just don't know what a human child looks like. In Dr Alphys' case, she didn't really mean the date at all anyways. Plus, Papyrus had to read a handbook for dating, and probably doesn't know what it means anyways.

As for the monsters who can tell that Frisk's a kid: Most of them are old enough to have been around during the War. Toriel, Asgore, and that turtle shopkeeper could have easily known what human children are like.

• I thought it was indicated that the monsters assume that anyone wearing a striped shirt is a child. At least that's how that one NPC kid says it.
• Papyrus also doesn't mention anything about romance unless you flirt with him, meaning that the non-flirt date could possibly be a play date. It certainly fits his childish demeanor. The flirt version has him reject you upon realising that he isn't feeling any romantic emotions, supporting the idea that he doesn't really understand what a date is.
  • Heck, none of the dates veer into sexual territory (Word of God claims Papyrus doesn't really even know what sex is), and the only romantic one is with Dr. Alphys...and only because you're roleplaying with her to try to get her to gather the courage to date Undyne.

ALL the characters are aware of the nature of the game

They know they are characters in the game and make comments if you attempt to name the fallen child using their name.

TheUnderground is kinda like a game version of Toon Town. The characters are just playing their roles and memorizing their lines. No time travel involved at all. The player are just sent to the last save point upon 'death', or sent back to beginning upon 'reset'.

The 'Hard Mode' is canon. No characters involved are actually 'dead', they just went off-screen and adding 'special effect' of disappearing. Note they also tried to make the 'game' child friendly, the monsters simply turned into the dust upon death.

According to the game, monsters are made of "magic". And what better excuse for the existence of magic is there other than nanomachines, son!

I actually do have proper reasoning for this however. When a monster dies, it disintigrates into dust. It could be assumed that this dust is just the nanomachines no longer functioning and thus becoming immobile. As for a monsters SOUL, it could be the program that holds these nanomachines together, and a boss monsters SOUL is more effective at keeping it together, and thus can linger outside the body for slightly longer.

Undertale takes place in the same universe as The Gamer

Flowey's Take That! toward watchers of a No Mercy playthrough is another one of his plans.

When Flowey talks to the player between Mettaton NEO's defeat and the battle against Sans, he refers to anyone else watching the playthrough as a cowardly sicko. However, this could also be an attempt to bait other humans into carrying out his plans. But instead of tempting them to prove their bravery and do a No Mercy playthrough of their own, he is instead trying to use Reverse Psychology; he hopes that the viewer is horrified by the events they just witnessed and will try to prove him wrong with a Pacifist run, which is exactly what he wants them to do because the climax of that run allows him to claim a veritable treasure trove of souls and regain his true form. After all, if your current pawn has grown so utterly depraved that you start to grow scared of them, why not try to recruit another?

The Monsters are vunerable to its effects as they are not compatible with it. Overuse and abuse of it can make you more murderously dangerous than the Getter protagonists. Chara was able to use it to remain in existence and attempt to regain an existance by jacking Frisk, and Flowey was engineered to be able to use it.

• Determination might also have a connection to Digisoul, explaining how you can one-shot monsters who seem powerful. They're made of some otherworldly pseudo-matter that reacts to human emotions.

Bathrooms exist in the Underground, but they're not like human bathrooms.

Well, of course they're not. Monster food doesn't require digestion, thus there's no waste product. Monster bathrooms are quite literally bathrooms, as in places where monsters bathe and wash up, because that's all they need them for.

Hard Mode, once it's finished, will be utterly nightmarish, and will reveal that nothing still is as it seems.

Perhaps in the style of Metsu in Irisu Syndrome — only this time, a happy ending is not guaranteed at all. Perhaps not even if you complete True Pacifist.

What would you expect, when the protagonist and the Fallen Child had the same name, and possibly were the same being? It's not telling you "your life is going to be living hell" for nothing. Plus, as stated above, you the player will likely never be the kind of person Frisk would be.

In fact, one ripe concept for ruthless Deconstruction here could be the very idea of Frisk—the video game hero that you want to be, but never will be. Because it's an impossibility, that you ever will be Frisk, in both meta and real-world senses. Obviously this would plunge the game into the cynical side of the sliding scale, but isn't that the whole point?

• Alternatively, the True Pacifist ending of Hard Mode would be a true Golden Ending where you save everyone. Even Asriel. What better reward for having the DETERMINATION to do the right thing, even when faced with impossible odds? Besides, why would the game compromise its own message for something as stupid as a Deconstruction?

In a future version of the game, you will get punished for trying to escape from selling your SOUL.

Meaning that no amount of f*cking with your savefile, clearing your Steam Cloud cache or automated patches will help you. The game will detect this, and it will only make things worse. If anything, there's always the registry to hide the necessary infos.

You cannot escape from your sins.

• There would always be someone DETERMINED enough to figure things out, even if it was in the registry.

Monsters have to be nice or else they will die.

Falling down is the monster equivalent of an incurable illness where the monster loses all hope and dies. If a monster encounters a lot of negative emotions, they run the risk of dying. Therefore, monsters have to be constantly nice. They painted humans as awful and evil to make everyone feel better and act nicer - monsters hate humans and don't want to be like them. On the surface, monsters can be horrible to humans, because humans won't die from being upset over hurt names, and are also ridiculously OP and could literally commit genocide if they wanted to. This is also why the monster population is so low when Frisk arrives - people are losing hope of escaping, Chara and Asriel's deaths and any deaths the previous Fallen humans may have caused would all have caused monsters to die off. It also doesn't get better on the surface if you were wondering.

Flowey's SAVE is ruined by multiple No Mercy Endings.

Flowey has, by his own admission, explored every possible route to take through the game prior to Frisk's arrival, meaning that he's killed everyone numerous times. Despite the lack of a Deal with the Devil with Chara, Flowey's SAVE is still tainted by his crimes, and as a result he's unable to ever achieve a perfect ending... which carries over to Frisk's SAVE, as Flowey is the only major character (save for Chara and Gaster]]) who doesn't benefit from the Golden Ending.

AU where instead of killing herself Madotsuki works up the courage to leave her room.

• After extensive therapy, she starts to piece her traumatic memories together, and her dreams, while still symbolic, elaborate, terrifying, and bizarre, start making a lot more sense. Undertale is those dreams, the Underground is the new dream world, Frisk is Madotsuki, Chara is a symbol of all her repressed negativity, Asriel is her lost innocence, and Flowey symbolizes all the places she thinks to look for that innocence but doesn't find it.
• All the other major characters are symbols of influential people or experiences in her life, and they all want to kill her at first because abuse and blah blah blah, but they become her best friends to symbolize her coming to terms with stuff and subconsciously forgiving them for the sake of her own mental health.
• Gaster is Uboa, of course. Whatever memory he symbolizes, it must have been pretty messed up, because her mind decided it would be best to just vaporize it and spread it thinly across the entirety of her being, just so it would never have to surface again, even if it meant the rest of her mind would become a little more corrupt.
• The amalgamates have something to do with the traffic accident.
• Despite Madotsuki being female, Frisk is genderless because Madotsuki doesn't really give two sh*ts about gender. She has no problem using male restrooms, if you'll recall.

Every player is Napstablook.

There's a reason the poor guy always feels like trash.

That's not to say he deserves it. Getting into the connection this implies between Napstablook and Chara, I think Napstablook is Chara's disembodied soul, which was never allowed into the body because of the body's, um, "neurochemical imbalance." Left to fend for itself, the soul grew away from humanity, grew a layer of protective magic, and thereby became a monster in its own right.

Napstablook may not be aware of everything the player is doing, but he gets the vague feeling that he's somehow metaphysically responsible for something horrible (and by extent f*cking miserable and full of self loathing) but powerless to stop it. Just like our conscience. As is customary of a lost soul, Napstablook let this grief and negativity consume him completely, until it became the whole of his self image, to the point where he's forgotten what he's even so sad about other than how much he sucks.

AU where Undertale takes places hundreds, or even thousands, of years after Zelda.There are a lot of similar character archetypes between the two games.

• Toriel's symbol looks like a muddled up version of the Hylian Crest.
• King Asgore and Ganon are both relatively similar in that they are both hoofed animals that act as kings of monsters, they both use fire powers and wield a giant trident as a weapon, and they are both Well-Intentioned Extremists (When considering Wind Waker).
• Papyrus and Sans are skeletons that act as guards... just like Stalfos in Zelda.
• Muffet is a spider that loves money, reminds me like how the Skulltula Men were cursed for their greed.
• Dr. Alphys is a lizard/dinosaur person, there's Dinolfos and Lizalfos.
• Undyne is not only a fish person like a Zora is, but even her appearance resembles a River Zora.
• Technology is highly advanced in comparison to ours. This could've easily started out from the technology seen in The Legend of Zelda: Twilight Princess.
• There are segmented blobs in both games, Moldsmal and Like-Like.
• You play as a person who can mess with time travel, much like Link can in The Legend of Zelda: Ocarina of Time and The Legend of Zelda: Majora's Mask.
• The hero of both games has an evil counterpart that looks similar in appearance, but is the complete opposite in personality. In this case, Undertale has Frisk and Chara, while Zelda has Link and Dark Link.
• The main villain, Flowey, is a psychotic, all-powerful being that you meet early in the game and torments you, also has a childish laugh, is represented by a large face, and needs the power of friendship. This also fits the description of Majora.
  • The main villain in both also happen to be innocent characters that got horribly screwed over (Asriel and Skull Kid).

The human SOULs each grant the following abilities:

• Red SOUL: Determination, for obvious reasons
• Aqua: Massive size (hence "'Ball' is 'Small'". A large character has less mobility than a smaller one, hence Patience is needed.)
• Orange: Extremely high offensive power (hence Bravery and "tough")
• Blue: immunity to the influence the others may have upon you (hence Integrity and why Flowey wasn't effected by their personalities fighting back, unlike Asriel
• Purple: Extremely high defensive power (hence Perseverance). It also grants the ability to trap enemies. Frisk was completely incapable of doing anything but fight when Flowey attacked him/her, could not escape Muffet's spiderweb, and Sans tried to trap him/her by not taking his turn.
• Green: Unlimited ability to heal (hence Kindness. Photoshop Flowey did not make use of this ability for obvious reasons.
• Yellow: Ability to use impossible attacks (such as flamethrowers and nukes with your face on them). It also grants the ability to use Always Accurate Attacks, including Flowey's infamous bullet ring.
• All of them together: Infinity Asriel has infinite ATK, DEF and HP, his combat background is a wave of cosmic rainbows, and his abilities all have awesome, stellar-sounding names.

All of the previous humans could save.

Omega Flowey has six save files for each soul he absorbs, and Toriel says that all the humans that fell down before are familiar. No one would be able to make it to Asgore without dying nice, it's near impossible.

Alternative to the above,it is a meta stat boosting

• Red : Ability to SAVE
• Aqua : High DEF
• Orange : Either high STR or SPD
• Blue : High ATK
• Purple : Either high WIS or INT or LUK
• Green : High HP
• Yellow : High ACC

Soulless Pacifist isn't that bad

If you decided you had places to go, Frisk/Chara simply crossed out the photograph. If you decided to stay, Chara simply possessed Frisk. It doesn't necessarily mean that Chara (will) kill everyone.

• And you know that Chara hates photographs from True Pacifist.
• It isn't that bad... well, except for Frisk being soulless. But hey, Flowey also didn't have a soul and he's still alive.
  • "I did [sell my soul], and look at me: I'm fine!"

The game is a prequel to Animal Crossing

After the return to the surface, humans and monsters once again live in harmony. The monsters establish settlements which are open to humans, these being the Animal Crossing towns. The Reset Surveillance Centre is established to prevent the abuse of SAVE, staffed by the Resettis, who can perceive timeline changes. Gross changes to the timeline are overseen by Rover, who, like Flowey, advises you against such things.

• Worth noting that the Animal Crossing WMG page has an inverted take on this theory: that your player villager is a fallen human kept blissfully unaware by the NPCs who are simultaneously keeping you hidden from Asgore and his subjects.

Most monsters don't know what sex is

Because they don't need to have sex, and instead get all freaky and meld their Souls together. Sans knows because he found out about it in the surface and remembered it the next reset. Monsters don't need to know and would probably be really confused by the idea, and shake their head, regarding it as a bit of human hilarity, remembering it fondly along with other great laughs humans have providing them, such as human food and humans interpretation of monsters.

The Artifact that the Annoying Dog absorbed would have given you magic

There are Dummied Out files that indicate that, at one point, you would have gotten magic. Though it's not certain why it was removed (possibly because it would have encouraged one type of run over another), it's possible that the artifact from the piano puzzle in Waterfall would have given you this magic (or even just a spell). The reason the room wasn't just removed was because it already appeared in a trailer, and the reason for the Annoying Dog arriving was because the artifact no longer had any purpose, so Toby didn't want you breaking the game by getting it (as in crashing, not getting something you weren't supposed to have). After all, the dog is Toby's avatar (supposedly).

The No Mercy run is an inversion/deconstruction of EarthBound's final battle.

In EarthBound, the protagonists use the prayers of everyone in their world to defeat Giygas' final form, but this eventually stops working and only starts working again when you, the player, contribute to it. In this game, Frisk is naturally predisposed to go for the True Pacifist ending, which means that any deviation from that (even if it's just to go Neutral) had to come from you, the player. In one scenario, the player saves the world from the outside, and in the other, the player destroys it (or at least, leaves it in a less-ideal state than if they had just let Frisk act naturally).

All Monsters possess DETERMINATION.

Think about it. Throughout the entire game, if you've reloaded a save and replayed some events, monsters can gain a sense of deja vu upon doing certain reactions all over again, such as Papyrus finding you familiar, or Toriel being able to guess whether you prefer cinnamon or butterscotch. Sans knows about humans beings able to manipulate time, and during the No Mercy route knows that the reason he feels that he's fought you before is because he has fought you before, and is even able to count how many times he's killed you or if you've killed him, because of his own DETERMINATION and research. Now, of course, they don't have enough DETERMINATION to manipulate time, or for their souls to persist (very long) after death, but they do have enough to gain that sense of deju vu, and have the drive to keep going. Monsters with more DETERMINATION than other monsters melt partially upon death.

Monsters experience the afterlife when their soul disappears.

When Sans dies, he begins to talk to Papyrus as if he were present. This could just be him losing consciousness, but it could also be him fading to the other side.

A more obvious point is that the Underground is populated by ghosts and skeletons.

The game will eventually be patched so that it's able to notice when its files have been manually tampered with

So that there can be NO way around the consequences of a No Mercy run

• Isn't that kinda pointless? If you wanted to make the game to NOTICE if the files had been tampered...that means tampering the game itself is possible in the first place.
  • The game already can be messed with that way, and hackers can always find a way. Allowing the game to notice is similar to the Genocide run's normal consquences- nothing is stopping you from doing the crime, but the game will do its best to make sure you also do the time.
  • Wouldn't that just lead to an arms race, where the game would add another file somewhere else to track whether the file was removed, but the player could just remove that file as well, thus necessitating yet another file, and so on?

Alternatively, the future game will encourage you to access the files

To break the fourth wall further so the player would be directly involved in the plot. Basically, something like OneShot

Some parts of the game were inspired by Fallen London.

More specifically, the Seeking Mr. Eaten's Name sidequest. Dr. Gaster comes across as an Expy of Mr. Eaten, what with him being removed from the game world almost without a trace, only known to those specifically looking for him. Second, the No Mercy route shares the theme of how far a player is willing to go to achieve 100% Completion, even if it means committing horrible atrocities and receiving an irreversible bad ending as their "reward."

Speculation about a potential sequel.

• Gaster will be either the Big Bad himself, or half of a Big Bad Duumvirate, the other half being the Fallen Child.
  • If the latter is the case, one will double-cross the other.
  • Jossed, it seems Gaster is actually on your side for some reason.
    • Gonna throw one further in this: who betrays who is dependent on the route. If it's a Neutral or Genocide route, the Fallen Child decides Gaster isn't useful to him anymore, while a Pacifist route will see Gaster pull a Heel–Face Turn.
• Whoever the Big Bad is, he, she, or they will exploit the fourth wall for his, her, or their plans.

Napstablook, Mettaton, Sans, and Papyrus are not undead/Blooky's depression.

We see what happens when a monster dies. Their body turns to dust, and they cease to exist. But Napstablook and Mettaton haven't turned to dust— they were just somehow always ghosts. All four never mention a past life as a human or other monster. Blooky's depression isn't a result of anything in a past life— their personality is just meant to be a contrast to their cousin. Mettaton is vain and extroverted, Blooky is self-deprecating and introverted. Similar to Sans and Papyrus, they're foils for each other.

• Alternately, Blooky's introversion is meant to go hand-in-hand with their passion for creating electronica. Many musicians in that genre, like Daft Punk, deadmau5, Phuture Doom, etc. are all anonymous, refusing to unmask or give out their real identity. Maybe they have an online persona that is mysterious and cool that releases their tracks under a pseudonym. Mettaton thinks highly of their cousin's work, and keeps encouraging them to start playing shows.

The game is set in the (very) distant future of the Dark Souls universe.

By now the cycle of light and dark has gone on for so long that neither has the strength to cause catastrophic damage to the world anymore, and most human souls have light and dark in roughly equal measure. The monsters are distant descendants of the Bed of Chaos, having also mellowed out after hundreds of cycles, except for Asgore's family (who may be descended from Gwyn) and the skeletons and ghosts (remnants of Gravelord Nito). This also creates a sort of equivalence between determination and humanity/dark; both can only safely be used by humans, both cause non-humans to melt when they're exposed to it (for example, compare Knight Artorias to Undyne the Undying), and both play a role in the ability to return after death.

• Asgore's Royal Guards use heavy black armour with horned helmets, as do Gwyn's Black Knights. The Black Knight armour resists fire, and the Royal Guards are encountered in Hotland.
• This would explain Dr. Gaster's experiments; if determination is really humanity/dark, then that's where the negative photon readings came from.
• As a corollary, Sans is a member of the Blades of the Darkmoon or whatever order they evolved into. His knowledge of the timelines doesn't come from Gaster's time machine (that's broken beyond repair), but because he has a Blue Eye Orb (maybe the orb is his actual blue eye?), which lets the user invade the alternate worlds of sinners to exact vengeance. Sounds a lot like what Sans does on a No Mercy run, no?
  • This would also explain why Sans is so nonchalant after losing his fight: dying as an invader doesn't kill you in your own timeline. Sure, he couldn't stop you, so the multiverse is still probably screwed, but he might have at least gotten a chance to go back to his own timeline before The End.

The Annoying Dog is Amaterasu

Because why the hell not? It is known in Ōkami that most people see Ammy as a white wolf... and since she is a god, there's no reason why she can't go in and out of the barrier at will. She took that artifact in the secret room and messed with the other characters because... well, she's a troll. She does all kinds of crap to Issun and some of the others, so I can see the Annoying Dog being Ammy.

(Could someone help me with linking things here... I don't think I know what I'm doing very well...)

Fixing the Genocide save corruption

What if this is still running off of Determination? A theory was that you couldn't fix the Genocide run taint because Chara now had more Determination than Frisk/The Player, so it wasn't in your power to fix it by yourself. Unless, of course, you're so determined to fix your mistake that you literally directly edit the reality of the world via the game's data files. Determination is defined as the power to shape reality using sheer force of will, so if you, The Player, go into your save file and remove the corruption, you're effectively out-Determination-ing Chara and thereby regain your control over the saves. This goes doubly so for the Steam version, as you have to do it every time you want to update as the Steam Cloud will replace the deleted files.

The screaming human face on Omega Flowey's monitor during the fight with him...

Betcha dollars to donuts it's Toby Fox himself making silly faces.

• That's impossible, Toby's a dog.

Unknown to most of the monsters of Underground, there are other monsters somewhere that use portal devices that resemble closet doors to scare out human children and collect fuel from them.

The idea seems to be a great crossover fuel.

Impossible or not, there were some monsters that seem to have managed to escape the barrier without killing a human SOUL

In particular was a bear trio stack consisting of a grizzly bear, a panda, and a polar bear. And now they are finding their place in the human world and the wilderness outside the mountain.

After the humans won the war thousands of years ago, the overworld was invaded by cosmic gem beings, and was nearly annihilated if not for the efforts of the rebel gem group sworn to protect the planet

Perhaps for the monsters, being trapped in Mt. Ebott would have been Cursed with Awesome. And it would have been safer if they stayed a little longer there until the crisis is averted.

There is this one theory that came from Twitter that Sans is actually Steven Universe who died from either cancer or a battle that didn't go well. The similarities might be uncanny given that both Steven and sans have the same height and smile a lot.

The barrier

The barrier worked similar to muggle repellent magic from Harry Potter. Only, it drives away ALL humans from climbing the mountain.

Somehow, children are less affected by this magic. Which explained why the souls belong to children.

The same magic also affected the mountain appearance. If someone tried to take satellite image of the mountain, it would only result in normal picture.

The other SOULs had PLAYERS too

Genocide run revealed the source of determination is the PLAYER.

Other souls have players too, they have ability to SAVE and RESET like Undertale Player. However, they either rage-quitting in between the game, or simply lost motivation playing, so they never finished the game. The souls are never revived and taken instead.

• Alternatively, it was a prequel where the player had no choice but to let the character they control die because of the plot.

The Yellow SOUL came from Linkara

He uses a magic gun and his hat kinda looks like a cowboy hat. He also has a pretty strong sense of justice, and can use magic in accordance with that SOUL power wmg above.

Theoretically, if Toriel and Sans were to become an official couple after the true ending...

...their child (not necessarily biological) would be named Arial.

The Light Blue Soul is a Shout-Out to Alice in Wonderland.

The color and the ribbon references the Disney version and the knife, the game version.

Some of the human SOULS fell down at the same time.

It would help to explain how so many were collected over a (supposedly) short amount of time. As for how their items are all sparsely scattered, it's possible that some died early on and the others were forced to run away withot them, even if the thought is sad.

Chara is the REAL final boss.

Chara is actually a boss that can be fought and beaten. But since there is no battle screen, not through conventional means. No, Chara, Sans, Flowey, everyone completely underestimates how much Determination you have and what you can do with it. While some can just save and load with it, you have the power to control the entire essence in which that world runs on. The way to defeat Chara is by deleting system_information_962 and system_information_963 from your App Data folder.

There's something else affecting the timelines.

Sans mentions that there's an anomaly in the time-space continuum, with timelines "jumping left and right, starting and stopping, until everything ends." We know there's at least two people capable of this, Flowey and the player, due to the SAVE mechanic. The thing is, SAVE files don't actually cover that. You can't switch tracks in the middle of a run. The best you can do is ruin a No Mercy or Pacifist run and start going for a Neutral run instead, and since you only have one save file, you can't switch between them to take different paths for each. In short, there's no "left or right" because whatever path you're on, you're on it until you either finish the game or reset. Flowey has been through all the timelines he can bring about himself, but he's in the same boat the player is. Added to this is the fact that Sans still makes that assertion even if your first run was a No Mercy run and you've never tried to steer off that path. It implies there is or was a third entity involved, capable of affecting the timeline in a different way.

• Additional guess: What Sans and co. were detecting was Photoshop Flowey. They didn't realize it, but they were detecting the multiple timelines created over in the Neutral Route by Photoshop Flowey's constant Save Scumming with the six SOULs. He was essentially "jumping left and right" in SAVE files to cheat on his fight with you.]]

There are already monsters living on the surface

In the True and Corrupt Pacifist endings the Monsters of Ebott seem to seamlessly integrate into the existing culture. But in fact it was only one kingdom of monsters cut off from the world.

• Makes sense. It's highly unlikely that every civilization on Earth would be warring with Monsters at the same time. It also explains why Frisk was totally unfazed by everything they came across underground; they'd already seen things like that plenty.

The Temmies set up a new village somewhere with Tem in the name

Such as the River Tem in England or Tempe in America.

• Yeah, I live in England and I know that there isn't a river Tem. There's the Thames which is PRONOUNCED "tems" and the river Teme, which is pronounced "Team", but no river Tem. Sorry.

Toby will release a deliberately bad sequel.

Jossed, we got an opening chapter for a legit sequel.

Any future updates/expansions/unofficial sequels will be based around the game breaking due to "glitches"

After the first major content "patch", there are few clues that may mean a future change.

• The new text in the Annoying Dog's room says it will take more than one patch, since "new holes keep popping up".
• Most of the new text from Sans and Papyrus has some character reacting in surprise, like even they didn't expect the change.
• Being able to access Gaster and his content without hacking officially turns him and his followers into glitch entities. If you don't get how that connects, check that page.
• Admit it, with all the hacking and data mining the game takes advantage of, isn't it odd how there are almost no references/responses to glitches?

Mostly speculation, and easily jossed, but it's slightly more plausible than some WMGs.

• The part about Gaster having a bigger role is confirmed.

Undertale's Neutral Route, where Flowey runs away, is Touhou 0

Flowey is the one who taught Marisa how to use star spellcards, and how to focus her LOVE to make her signature Master Spark...

Before Marisa betrayed Flowey like Chara does in the Genocide Route, she used Flowey's uprooted 'body' to fly and boost her magic in Touhou 2.

The barrier? It expanded with time. Notice how Touhou seems to take place in the future, as hinted in the games and official mangas.

The Hakurei Barrier might just be patching the original barrier. I'll update this WMG later with more thoughts and potential evidence.

Of course, anyone familiar with Homestuck mythology knows that everyone in a doomed timeline ends up dying sooner or later. Genocide Route leads to a "sooner" scenario, and the Neutral Routes lead to—for some to most—a "later" scenario. True Pacifist Route is, of course, then the alpha timeline.

It is completly possible to rescue Asriel.

You just need a mod. It's excercising the player's will as The Anomaly and their ability to change spacetime!

Considering that Temmie is the Author Avatar of one of the game's developers, and that you have to fork over a lot of gold to pay for both her college tuition and the armor itself, it's possible that this is a clever jab at the idea of paying extra real-life cash to a game company to get special powerups that make the games easier.

Knowing that their town has been slowly decaying and is having doubts about a soda corporation would overtake the town, Frisk decided to go into the mountain to ask the spirits for help despite the townspeople's warnings of children disappearing. Upon there, they stumbled into the cave, and you know the rest. By the time Frisk and the gang came back to the surface, the old farmer's grandchild had arrived and would have revitalized the town by now.

A sequel would have the fact that many players erased the consequences of a Genocide run as a plot point

Many players figured out how to avoid consequences after doing Genocide by modifying game files. However, that ends up leading to unforeseen consequences, making things MUCH worse, somehow.

Chara is related to the Forgotten from Gemcraft.

They're both demons who have impressive offensive powers but require help to break large magical walls, who rely on others to fulfill their ends by possessing them and live in worlds full of monsters.

The high contrast screaming human face on Flowey's monitor during the final boss fight with him in the Neutral Route are representations of the human souls he has absorbed.

Flowey is currently using 6 human souls to power himself and ascend to godhood. This means he has seven "minds" within his body all at once and can feel all of them (he comments that he can "feel them wriggling"). However, due to their incapacitated nature, they are unable to do anything to stop him unless he himself is significantly weakened, only able to aid the protagonist during the short windows of time Flowey attempts to use their individual powers to torture the protagonist, which is the time at which he is weakest. The screaming human faces on the monitor are actually an amalgam of those of the humans trapped in Flowey's body (hence the disturbing Uncanny Valley appearance), screaming silently as they fight Flowey to gain control for a brief moment.

In the "Anarchy" ending, a new ruler is eventually found, and it's...

Jerry.

• Dear god! Not even a Genocide player would be so cruel as to let that happen!

Let's compare. Mami's associated color is yellow, just like the SOUL. The yellow SOUL is connected with Justice and Mami's theme is "Credens Justitiam", which translates to "Believing in Justice". Also, the associated weapon with the SOUL is a toy gun and what does Mami attack with? Guns!

The Human Mages died to create the barrier

It’s literally their souls’ remnants that make up the barrier itself, equaling a bit less than the full power of seven ‘’live’’ human souls, thus justifying the incredible power needed to break it. (Also see my “Your actions…” theory below for more thorough discussion of the Barrier.)

The Human and Monster Souls don’t have to share a body to pass the barrier

A co-mingling of DETERMINATION and love could be truly all that is needed to allow passage from the magic there. If so, a deep love (either familial or romantic), would be enough to allow passage. Presumably, Chara and Asriel could have walked through, with enough confidence. (Again, see below for more on the Barrier itself.)

The Offspring of a Human/Monster pairing could pass the barrier

It would have a soul containing both monster and human elements (DETERMINATION and love), which in this theory, is enough to cross the gate. (Also, see below… yet again.)

Your actions as a player represent the attitude of the society Frisk comes from

While it’s taken as canon that Frisk’s own personality and desires match those of someone on a True Pacifist run, this theory is that he’s ‘possessed’ by the overall spirit of Humanity when he falls through the hole into the ruins. Presumably the Barrier actually extends over the entirety of the Underground, and Toriel’s not preventing her fellow monsters from building a ladder and climbing out of an open hole. The Barrier, being made of human souls, is probably pretty sensitive to the feelings around it, and would imbue any human passing through it with said attitudes, overriding their own. This happened with Chara, being filled with humanity’s self-loathing (think about how often disgust is shared nowadays about this or that portion of society, or oneself, etc. Then add in all the injustice and rage against it. Filter that down, and it comes down to a pretty solid hatred) at the time of his falling, and that fueled the plan he made with Asriel. By the time Frisk falls, things could have changed, leading to a True Pacifist run, be roughly the same (various types of Neutral runs), or have gotten worse (Genocide). This is also why the True Pacifist ending would really be as good as the cutscenes imply, if most of humanity is as loving as Frisk, then the monsters really would have nothing to fear. Yeah, there will probably always be pockets of hate and racism, but the monsters would be almost completely safe.

Memoryhead is the result of a failed attempt to bring back Dr. Gaster

It seems pretty obvious, given the lack of recognizable monster parts in its battle sprite, and the name “Memoryhead,” that said amalgamate has something to do with W.D. Gaster. He only exists as a memory, and then only to some. Perhaps, before his memory faded too much for anything to happen, Alphys tried imbuing whatever dead skin cells, DNA, etc. that remained on his old possessions with DETERMINATION, but didn’t see any results. It was only after the other failed tests, that some of the remaining monster dust intermingled with the microscopic remains of Gaster, and his presumably great magical power, to create Memoryhead.

Humans don't have magic at all; they have sufficiently advanced technology and the barrier is actually a temporal displacement field.

Which is why Determination, a human characteristic, confers the power to manipulate the timeline. The underground is physically underground, but the barrier works by taking the stretch of time between the monsters being sealed and the monsters going free, and separating it from the rest of space-time. The "way in" from the mountain is actually a time portal.

The "Empty Gun" is actually a toy gun.

If we're going with the general consensus that every human that fell down and was killed was a child, this makes more sense. It could be an older toy gun that looks a lot more realistic than toy guns do now, hence why Bratty and Catty can't tell the difference. Or maybe they wouldn't be able to even if it was a more colorful one, if they'd never seen a real gun before finding the Empty Gun. In the latter case, depending on how old Frisk actually is, he/she probably might not know any better either and would just take their word for it. There's also the meta-excuse of preventing repetition by having two "Toy X" items(this and the Toy Knife).

You could make a similar argument for the Burnt Pan, but it's less of a stretch to imagine a child being allowed to play with cookware than with an actual gun.

Some of the monsters chose to return to the Underground.

Most of them lived there for their whole lives.Is it such a stretch to think that some of them might of chosen to stay with the Good Old Ways?

On the surface, Monsters win fights through a combination of interface screw and pacifism.

All ancient warriors who possessed the knowledge of fight mode are dead and buried.Modern weapons are cold iron free and don't harm monsters.As a result most soldiers will be really confused and choose to flee.

• That makes zero sense. First, a child can beat monsters with a stick, cold iron never came up. Second, how does pacifism come up at all? The way you explain it, monsters can basically slaughter humans with impunity, thus making the pacifist ending the WORST ending.

• Graphics either redrawn at a higher resolution or in some level of 3D, either full or as a Sprite/Polygon Mix (either way, Photoshop Flowey would be in full 3D to emphasize the "wrongness" in his design).
• Rearranged soundtrack.
• Battle backgrounds beyond the occasional boxy shapes (except for, again, Photoshop Flowey, because you and him are the only things in the world at that point).
• Muffet becoming a major character, for multiple reasons (for consistency with other SOUL users, for representation in the Asriel fight, to serve as the boss of Hotland so it doesn't have a disproportionately high kill count in a No Mercy run, sheer popularity).
• Regarding Flowey and Chara crashing the game:
  • Flowey: Instead of the game window closing after he absorbs the human SOULs, the screen cuts to black, several glitchy noises play, and the game appears to restart until the intro screws up and you're taken to the "My World" file. Losing to Photoshop Flowey at any point simply takes you back to the file select.
  • Chara: Again, since there's no game window, the screen of "9999" simply shakes from side to side a la a dying monster, and the black screen with wind appears immediately. The wait time before Chara makes their offer is drastically reduced (for battery life/patience reasons), and they will automatically reappear to make their offer given the same amount of time. (On the 3DS, Chara's attack if you refuse to destroy the world could take advantage of the system's 3D effect...)
  • In both cases the crash would work as in the default game on PC.
• Of course, meta commentary on the game being a remake, particularly regarding the added content.

A theory about Chara's motive for potentially going through multiple resets but only ever doing Pacifist Runs.

If you keep resetting but only doing Pacifist Runs, Chara's motive for resetting so much is that they still haven't given up on saving Asriel. Despite being a reference to the player, Chara has repeatedly shown that they have a personality beyond just being the player so they would need some kind of motive to reset unless your influence over them is just that strong.

The Pacifist Ending leads to another war.

Think about it. Nearly every monster attacks you on sight, never stopping until you are dead or you convince them to stop, most likely by them getting confused at you refusing to defend yourself long enough to escape. Anything saying that they don't intend to kill you is really just Frisk trying to convince themself of that, they really want you dead. At the end, the barrier is opened. However the war goes this time, it's ending in extermination. The ending you see, just another one of Frisk's delusions.

• Word of God confirms that the Pacifist Ending is exactly as it seems.

All monsters are ghosts that became Corporal.

Think about it, the underground is implied to have a large ghost population and also many skeletons, the rest of them taking on animalistic chararistics. Eventually ghosts that posess remnants become a fusion of the object that they have taken.

Consider that the monsters were banished underground a very long time ago; if they did eat human food, they presumably ran out after a while, and so they've most likely been exclusively eating monster food for a long time. Since monster food digests completely, they don't need toilets, but present-day monsters still have a concept of "going to the bathroom". In their case, "I have to go to the bathroom" may actually mean "I have to take a bath/shower". Consider also the two monsters who use this excuse: Papyrus is mentioned to take showers in an earlier bit of dialogue, and after Alphys gives the excuse, she hides in an elevator to the True Lab, which does feature a shower/bathtub in one room.

The former Humans aren't as bad as the Monsters thought.

So supposedly they go to war to capture monster souls....but when they win, they seal the Monsters away. This isn't to say there weren't racial tensions on both sides, but those actions don't match.

• Afraid not. The humans didn't go the war to capture monster souls, a mural in Waterfall quite clearly states that the humans launched a pre-emptive attack because they feared the monsters' ability to take a human soul.

Undertale and Cave Story are in the same universe. (SPOILERS)

(I'm also posting this on the Cave Story WMG page)

The timeline goes something like this: Long ago, monsters and humans lived together in peace. The monsters were native to a floating island, and the humans came from the surface. Monsters and humans could travel between these places as they wished. That is, until a monster called Ballos was imprisoned and tortured until he lost control of his magic and destroyed a city. This started the war between humans and monsters. However, the account told in Undertale isn't fully accurate; Humans didn't have any magic, but they did have Sufficiently Advanced Technology allowing them to create an army of Ridiculously Human Robots, and quickly forced the monsters underground. A force field was set around the caves, locking the monsters away.

Ten years later, a group of researchers came to the island, to get betrayed by The Doctor. He convinced them to disable the Barrier, and stole the Demon Crown, a medium for Ballos' uncontrollable power. Using the Red Flowers, he tried to create an army from the peaceful Mimigas. But, thanks to a pair of amnesiac robots left behind from the war, his plans were stopped. And even more, they managed to destroy Ballos, freeing the monsters from his influence. Then, for some reason, someone reactivates the Barrier on their way off the island^note.

With Ballos gone, the Red Flowers lost their powers and their color (Becoming known as golden flowers), but retained a few supernatural qualities, allowing them to capture the essence of a dying Mimiga, or, as they became known later, Boss Monster, and gained sentience when the scientist Dr. Alphys tried using them as Soul Jars^note.

Many years later, some humans settled on the island, having either forgotten the war or dismissed it as legend. A human child fell into the underground, since the now-ancient Barrier was starting to deteriorate. After a long, heartwarming, timey-wimey adventure^note, they and a restored Asriel destroy the Barrier with the power of all the souls in the underground, allowing monsters and humans to live together once again.

How much magic power a being has depends on the strength of their SOUL, and skill could depend on SOUL type; thus, by default, Humans are Unskilled, but Strong whereas Monsters are Weak, but Skilled, but either one can overcome their respective shortcomings via either training or absorbing the opposite-type soul.

We know Humans do have access to magic since that's how they sealed the Monsters underground, yet that's the only instance we hear of Humans using magic(unless the ability to SAVE uses magic, which is a WMG in and of itself). Since absorbing a Human SOUL gives Monsters a huge power boost, this implies that SOULs have some connection to magic power. Supporting this is the fact that the two strongest monsters we fight—Toriel and Asgore—are stated to be a type of monster with an abnormally strong SOUL that can briefly persist after death.

Keeping the two beings in balance at first (until the Monsters' vulnerability to killing intent upset that balance) were different skill/strength ratios; Humans had stronger magic, but a smaller pool of spells that they could use. Monsters have weaker magic, but a more diverse range of spells. However, both species, if they so desired, could overcome those limitations through training—Undyne became strong enough to take on Asgore head-on via years of training, so perhaps Humans could increase their repertoire of spells via extensive training and study.

Of course, the Monsters have a shortcut—they can skip right to the end power boost by absorbing a Human SOUL. Perhaps Humans can also gain greater magical finesse much faster by absorbing a Monster SOUL(most likely the spells that the Monster used beforehand, since different Monsters seem to be able to use different attacks). Of course, neither side knew this since Monster SOULs are too weak to persist long enough to be absorbed, which is why they came to the conclusion that a SOUL-Boosted Monster had no counter. In reality, all other things being equal, a Human with a Monster SOUL would be able to stand toe-to-toe against a Monster with a Human SOUL in both strength and skill.

Mettaton was never planned to have a dating segment like Papyrus and Undyne

Toby's comments on the kickstarter page about dating mechanics and having a "Robot Husband" most likely refers to Mettaton. But in this case, had the idea ever come to fruition, it wouldn't have been a typical dating segment like the first two. Instead it would've been another television segment in Hotlands, specifically it would've been a soap opera in which Mettaton plays your romantic opposite and tries to kill you.

Undertale is set in a parallel version of Mewni

Rather than being driven into the wastes by mewman (here called human) settlers, the monster race was driven underground entirely, and sealed away with magic. After that, Mewni society marched onwards, developing technology and culture resembling Earth, or possibly borrowing said paraphenalia from Earth directly. Then seven or eight humans fall down a hole, and the story plays out from there.

Think about it, I think there are too many similarities to be a coincidence. First of all, both of them are Knights who like to fight, who wear armour with red hair being exposed through them. Second, Dizzy, who is a clone of Justice, has a wing called Undine. I don't think that's a coincidence and I think Toby genuinely loves the game Guilty Gear. Because he's just that kind of guy. Plus the theme of Undyne is called Spear of Justice.

The red SOUL's trait.

Positively nowhere in game is the red SOUL's trait stated to be Determination, so I purpose this: the red SOUL's trait is 'being yourself'. Obviously this doesn't fit prettily in one word like all the other traits do, but there is some evidence to this: first, in every route examining the mirror gives you a message—"It's you!", "Despite everything, it's still you", "It's still you, Frisk", "It's me, ____"—that affirms that it's you or someone else like you that's looking in the mirror.

Obviously this could be written off as just flavor text for the mirror, so example number two, the Ball Game: finishing the game in under 10 seconds nets you the red flag (which leaves 'Determination' out of the other SOUL traits), and finishing the Ball Game again in the same fashion nets you the red flag once more with a new message: "Try as you might, you continue to be yourself."

And finally, in Sans' Neutral judgement speech he starts off by saying "truthfully, it doesn't really matter what you said. all that's important is that you were honest with yourself."

• But everyone is themselves...
  • When Papyrus pretends to like whatever Undyne likes even though he previously said he dislikes those things he's not himself. Alphys keeping the secret of what she's done from everyone and pretends to be a hyper-competent supporting character to you she's not herself. When Toriel injures you to near death to keep you in the Ruins she's not herself. When Asgore declared war against humans on a snap decision he wasn't himself. A lot of characters in Undertale aren't true to themselves and you even help most of them out.
• Further evidence: 'Determination' is a trait all human souls are shown to have, so either A) all souls have all traits in some quantity, or B) 'Determination' isn't the red soul's trait.
  • Monster souls are said to be made love, hope and compassion. Those are multiple characteristics in one soul. So it seems more likely that all human souls have all those traits in some capacity.
• Integrity is already a trait, though.
  • Some people have taken to calling it 'sincerity' or 'individuality'.
• "Being yourself" could be understood as a scrap category for humans who do not fit any of the other 6 categories. It should also be noted that you only receive the red flag if you accomplish your goal very quickly, which can however only be done through rigorous practice (or incredible luck), during which you may or may not receive all the other 6 flags - which would agree with the initial description of the red flag, which initially lists the 6 traits as keys to your red flag success, while simultaneously labeling the game itself in red color (and the narrator also labels the hole in red, through that was probably just for sarcastic emphasis). What this ultimately means is up to speculation. Maybe the ball game represents a pointless task, ergo that red is somehow an 'empty' or 'unlabeled' trait, or maybe it's something else entirely.
• It's noteworthy that in Deltarune, the soul colour is red even though Kris isn't in control. The Game makes reference to the fact that the soul is Kris' for the moment. If the red soul were really about being yourself, it seems odd that Kris possesses a red soul that doesn't allow them to be themselves. Determination seems more likely. It might be more that the Player is being themselves, however that is also a very flimsy reason because it's stated in both games that the Player is only just controlling the actions of the player character, and that there are seprate beings inside the game itself. It seems most likely that all souls have a bit of every trait in them, with the trait colour just being the defining characteristic. After all, humans aren't two dimensional characters.

Asgore didn't kill all the six humans before Frisk by himself.

He indeed killed the light blue and orange humans, the ones who fell first. That's why the light blue laser and the orange laser are so extended: he shared what he learned from them. But the only one who has "Green" attacks is Undyne. So she killed the Green child, and got his Patience. Muffet killed the purple human, and Alphys got the Yellow one. That's why they can do their special attacks. For the Blue child, the ballet girl, she was deemed the most dangerous and the shoes were dusty. As in, "dust from monsters' corpses." She was defeated by Gaster, who gave her powers to their sons, Papyrus and Sans.

• But Undyne has never seen a human before; she only knows about them from watching anime.
• Additionally, the light blue soul's loot is found in the Ruins.
• "Jossed, although these tweets have been deleted since."

Asgore is far more powerful than he appears

He destroyed the Mercy button. No one else in the entire game manages this. He seems so easy because he can't bring himself to harm someone who is the spitting image of his child who committed suicide. As a parent, imagine what he must be going through. Destroying the Mercy button must have been a way to harden his heart, not giving himself a way out. Secondly, his trident turns red. The color of determination, yet it never shows that color again. Maybe he couldn't harness that power because he didn't want to fight, deep down. Everyone seems confident you will be no match for Asgore, even Undyne the Undying. The battle with him supports this. Talking to him and telling him you don't want to fight lowers his attack and defense. It is canon that it is a struggle for him to fight you. Considering Chara took over in the Genocide battle, and Flowey warned him, maybe he told him who Chara was, and he was trying one last feeble effort to convince his child to come back to the light.

• This seems to be pretty close to canon, considering how high his stats are when you CHECK him. Then consider that he trained Undyne, who is another one of the strongest monsters in the underground. Asgore had to have gotten his reputation somehow, and the monsters' faith in him seems to be pretty well justified by that. He's just deliberately holding back for the various reason stated above, plus actually being a pretty nice guy. Asgore seems like an Apologetic Attacker before the fight, so it's quite likely that, on top of everything else, he actually hates fighting, in spite of how strong he is.

Frisk is an alternate universe version of Trace

There's actually quite a few parallels between the two, when you look at them side-by-side.

• Trace is a Reluctant Warrior who prefers to avoid killing whenever possible (attempting to reason with bosses, just running past Xedur-Hul,, and trying to spare Athetos, for example.) At the same time, the most common depiction of Frisk is a Badass Pacifist All-Loving Hero who refuses to fight unless there's absolutely no other option.
• Both Trace and Frisk are able to come back at a Save Point whenever they die. Trace achieves this through cloning, Frisk through Determination.
• Both of them have some kind of counterpart known for committing genocide. Chara, who Flowey mistakes Frisk for, only makes their presence known at the end of a Genocide run. Athetos, the original Trace, has already committed genocide on Sudra by the time Trace is cloned.
• Going from the above, both can be corrupted into being just like their counterparts. Through the players actions, Frisk can kill every monster in the Underground, and the hidden endings of Axiom Verge imply that Trace is destined to become Athetos.
• Trace, like Athetos, is a "Patternmind", some kind of Reality Warper. While it's never really explained beyond that, it can parallel Determination allowing Frisk to SAVE and RESET.

Conclusion: Trace is a version of Frisk who never fell into the Underground and discovered the power of Determination, and went on to become a scientist as an adult.

The Amalgamates aren't really that tough; Frisk just refuses to hurt them

Frisk begins the game with very little autonomy. You have virtually complete control of them. However, the further you go along the True Pacifist route, the more autonomy they gain. By the time you're deep enough into the True Pacifist route to reach the True Lab, they've gained enough autonomy to defy you, as you can see if you tell them to be mean to Snowdrake's mother. If Frisk has enough control to stop you from committing cruel but non-violent actions, then they probably have enough control to stop you from committing violent actions. After all, Frisk really doesn't want to hurt anyone. Otherwise, the Amalgamates shouldn't be that hard to kill since their forms are unstable. Asriel Dreemurr, of course, is a different story; he really IS strong enough to take no damage from Frisk's attacks.

Soulless Pacifist is actually the BEST ending possible.

And the reason why is because the Anomaly and the threat of the happy ending being reset are removed by an elaborate deception from a Fallen Child who is a benevolent being masquerading as a malevolent one. The problem with the (normal) Golden Ending is that there will always be the threat that the Player/Anomaly will be curious to know what happens if they reset the timeline and kill everyone, proceeding to do exactly that. And at the end of the Genocide Run, Chara steps in and puts a stop to it by claiming Frisk's soul for their own. This has two purposes: firstly, every time the Anomaly tries to get a Happy Ending and ignore the consequences of their actions, the Fallen Child will always be there to remind them of their crimes. But more importantly, the Anomaly will think that the Golden Ending is ruined forever and abandon the game/universe since there's no point in trying anymore. Chara isn't ACTUALLY doing anything to harm Frisk or the monsters, but they have to make the Anomaly think that the cast is doomed no matter what. Assuming Chara's ploy succeeds and the Anomaly leaves, they are then free to carry out the Pacifist ending themselves and let the cast free onto the Surface without the threat of the Anomaly or Resets hanging over their heads.

• There is also an alternative reason why this might be the best outcome. Assuming the theory that Chara is the player - supported by Flowey's final talk with the player, which ends by Flowey calling them using Chara's name, Chara might leave Frisk and the rest of the world behind and move on to afterlife. But in this ending, they stay. It's not much, and it's certain that they will attempt to hurt someone, but it DOES give them hope to be SAVED later on, as opposed to dying forever. Not even Asriel decided that moving on will be the best option for him, even through his constant suffering.

Determination is a combination of the other six traits.

The Ball game hints towards the idea that Determination is actually a composite trait of the other six:

Bravery. Justice. Integrity. Kindness. Perseverance. Patience. Using these, you were able to win at "Ball Game."

This means that every human soul contains at least a small amount of every trait, since Alphys was able to extract determination from them. Undyne's soul also contains a small amount of every trait, since she has determination. Additionally, which traits shine during your playthrough depends on which route you go for.

Flowey will become the next McDonald's mascot.

A wonderful idea, isn't it?

Undertale, NiGHTS and Coraline are from the same universe, but in different times and/or worlds.

Both are surrounded about magical beings, journeys of children into magical worlds, and Undertale and NiGHTS even include Plot Coupons with colors (The Idea of Courage seems as strong as the SOUL of Determination,and both share the red color). The Monsters, the Underground (after the sealing of the Monsters) and The Other Mother and her Other World may be ancient magical worlds and beings for the waking world (altrough there are theories that the first visits of Coraline on the "Other World" are in dreams), and Nightopia, Nightmare and their inhabitants may be ancient magical worlds and beings for the dreams. Possibly, the three universes may pass on an alternate version of Earth where magic is both existent and ancient. Chara, the six humans, Frisk, Coraline, Elliot, Claris, Will and Helen may be one of the few children and even the most important children to get into contact with the magic of their world, but of course in different parts of their worlds.

Undertale takes place in the same world as Gothic, albeit in the future

Like in Undertale, multiple mages create a barrier - it's even called the barrier - to creaan unescapable prison, just for humans instead of monsters. The barrier around the valley of mines took 12 mages to create, as opposed to 7, because the barrier in Gothic was greater, being created to shield an entire valley as opposed to a single mountain. The mages and their focus stones were not trapped this time, because unlike in Gothic, no Eldritch Abomination disrupted the process. The fallen human was an avatar of Beliar that planned on creating an army of monsters to overthrow King Rhobar, which is why they entered Mount Ebott. When the fallen human realised how weak monsters really are, they decided to nurture Asriel to become an Invincible Villain by tricking him into absorbing his soul, making Asriel the new avatar of Beliar, and making him attack humanity, which backfired as Asriel refused to attack the farmers and died, their combined soul reincarnated as the Krushak, also known as The Sleeper. When the combined corpse of Asriel and the fallen human was reanimated as Flowey, the fallen human became something lesser than a ghost. Millenia later, it tried to possess Frisk in order to get a new body. If you play the Genocide Run, they succeed in destroying the underground, but fail at escaping the barrier. In the soulless pacifist run, they succeed at entering the outside world... and destroys the world... I guess? Anyway, where in the world of Gothic is Mount Ebott? It is of the many mountains on the island of Khorinis, the human city you see in the Pacifist run credits is the city of Khorinis, which became a metropole after the war between the gods ended.

Flowey in The True Pacifist Route actually absorbed Frisk's SOUL as well.

And the battle between Frisk and Asriel is actually a Battle in the Center of the Mind with Frisk fighting agains't the dominant consciousness (Asriel) for her freedom,for the freedom of the six human SOULs,for the freedom of the rest of monster-kind and to make Asriel purified,before he can use his new powers to end/reset the timeline. After Asriel leaves and frees the SOULs of everyone,Frisk is dropped alongside her main friends,but in a unconcious state.

When he absorbs all the monster SOULs in addition to the trapped human SOULs, you're supposed to remember that one sign in Waterfall that said something like "it would take every monster SOUL in the Underground to match the power of one human SOUL" and realize that he has, technically, absorbed power equivalent to seven human SOULs. This is also supposed to explain why he can only do this on a Pacifist Run — if you had killed even one monster, there wouldn't be enough SOUL power for this to work.

But isn't it odd that there are exactly that many monster SOULs left? And the descriptive text on the sign seems more like a colorful metaphor than a mathematical fact... But when you think about it, the only differences between a no-kill Neutral ending, and the Golden Ending, are all the result of Flowey's manipulations. He thinks the sign in Waterfall is stating a mathematical fact (remember, he's really just a kid, so his critical thinking skills are underdeveloped), so he won't do these things if you kill a single monster. He won't tell Alphys "I KNOW WHAT YOU DID", he won't tell Papyrus to call everyone into the throne room, he won't encourage Toriel to hurry up so she can stop you from killing Asgore (and may even impede her from doing so — he can block doors with his vines, after all).

As for why he doesn't enact The Plan if you kill nobody but don't enter the True Lab... He seems to have a flair for the dramatic, despite having no SOUL and ostensibly no emotions.

Flowey/Asriel and Chara are the most flagrant fourth wall breakers in the game, and both lack a soul for the majority of their screen time. Souls act to "anchor" a person to the world, which is why losing one means not only seeing the world as a game and effectively reality warp it by understanding its fundamental nature, but seeing others in the game as fictional characters that exist to entertain, instead of people with rights. Both of these things being major components of both Flowey's character and that of a player who does the Genocide route.

That area will remain a PlayStation exclusive, but instead we'll have an equivalent area somewhere else.

• People already know about the Shrine so it loses its suprise/secret value.
• Slightly-confirmed: the shrine itself is still there, but it's wrecked and no longer serves it's original purpose.

The game takes place in Frisk and Asriel’s Happy Dream.

In life, they were a pair of Serial Killers who were caught and sentenced to death, but became subjects for a new version of the experiment. Chara and Asriel created a dream world and made up a whole backstory for it. The monsters and souls are based off thier many victims. They had fun, and Asriel was the first to start feeling guilt. However, they both got tired of it, and prepared to mount an escape by destroying the “barrier” (that Dreamsend Inc. made to trap them in the Dream till they accomplished thier mission). The plan failed, however, and Asriel was given the new form of Flowey to keep him planted in the Dream. His soul represents his slowly developing guilt that was destroyed. He had no emotiion, and proceeded to trash the Dream world. Eventually, Chara was given a new form as Frisk, and was released in the dream world to truly learn guilt. In the Neutral ending, neither of them succeed and become eternally asleep in the dream world. In the Genocide ending, they escape and go on a killing spree inside the facility. In the Pacifist ending, they finally succeed in reforming and are given back thier old selves, and presumably allowed to wake up.

It adds to the ironic humor of Undertale.

In a hypothetical XBox version, money dognated will go to repairing the Dog Shrine, rather than simply building it.

When first found, the shrine will appear in its damaged state seen in the Nintendo Switch version. But here, the donation box will be usable, and each set of dognations will be put to repairing one piece of the shrine until it's returned to its fully completed state from the PS4 version.

As a silly little Take That! from Toby to the theorists.

Determination has a SOUL color, but it's not red...

...it's golden. In Deltarune, Asgore has six colored flowers representing the six SOULs... and one golden flower. Furthermore, the save point which is made of Determination has the same color as Floweys petals but not the same color as the yellow SOUL. Frisk may have a red SOUL and be particularly determined, but that does not mean that red stands for determination. Chara's SOUL is also red and nowhere is it stated that they were particularly determined nor that they ever loaded or saved. Furthermore, the red BALL GAME flag states this:

Bravery. Justice. Integrity. Kindness. Perseverance. Patience. Using these, you were able to win at "Ball Game."

Where "Ball Game" is written in red. Therefore it is likely that a red SOUL has a equal amount of all SOUL traits.

The red souls trait

...is hope. Both Frisk and Chara have red souls and are described as having hope in their eyes, and you know what they say about souls and eyes.

Boss Monsters are the descendents of Monsters who absorbed a Human SOUL

This idea was brought about by two questions — 1): how does anyone know that monsters are able to absorb human SOU Ls at all? 2): why are Boss Monsters so different from other monsters in the first place?One possibilty is that Asgore and Toriel's ancestor(s) were able to absorb a human SOUL at some point, although the details of how are unknown. Either way, when the ancestor(s) had children, these offspring inhererted special powers related to the human SOUL, albiet very watered-down by comparision.

The Humans mages are descended from a human who absorbed a Boss Monster's SOUL.

On a similar note, how is it known that a human can absorb a Boss Monster's SOUL? Also, why were humans able to use magic in the past, but are unable to do so now? It could be that humans, unlike monsters, do not have the natural ability to use magic and thus must get it from another source, in this case being a Boss Monster's SOUL. Once again, the decendents of this human were able to inherit watered-down abilities. However, this linage of magic-using humans has since died out for some unknown reason.

The true reason for the war was simple human greed.

Long story short, Boss Monsters are functionally immortal, but can transfer their immortality to their children.Gee, I wonder how many humans cared about the 'indisputable fact' that only monsters can receive immortality.Alternatively, perhaps it is monster dust, snorted lightly as it spreads like ashes on the wind, that gives humans magic.Seeking power and immortality, the human mage-kings riled up the population and waged a race war just so they could capture the boss monsters alive.Eventually, most of the Boss Monsters were killed off in battle or during experimentation, and the only thing left to do was deal with the surviving monsters.

Reasons for sealing away the monsters

• Some of the only sane mages realized that if they killed off monsterkind forever, it wouldn't be long before muggles looked at mages funny.
• The humans wanted to preserve the only remaining monsters so their descendants could eventually unseal and experiment with new generations of monsters.
• A few of the monsters helped the humans, reasoning out of mutual benefit that (A) the war had decimated both sides and if either side fought to total extinction the other would be soon to follow, and (B) the human kings needed a scapegoat to blame, and if that scapegoat was contained and preserved, all the better.

Sealing monsterkind backfired. Without monster Dust on the wind, the humans slowly lost the ability to cast magic. Now none of them could undo the seal and collect magic from their monster farm.

...Sort of, anyway (in Undertale's case, I guess it depends on the timeline). There's no denying all three game series have a lot of things in common (with Touhou being one of Undertale's many inspirations, and Len'en pretty much being a series based on Touhou). That said, they all feature humans doing things beyond the impossible, with or without magic (not to mention Suzumi Kuzu in Len'en has abilities akin to Frisk and Flowey's resetting and timeline manipulation).

Assuming this is true, this would make the monsters in Undertale a sub-species of the youkai in both Touhou and Len'en, or vice-versa, but the thing is, the youkai are pretty much Japanese monsters created by human fears, whereas in Undertale, the monsters don't have connections to human fears, but we do know that they're made of magic (plus they are capable of killing humans using said magic). You could interpret this as youkai resembling monsters if they didn't appear humanoid in Touhou and Len'en, or perhaps the Undertale monsters aren't related to youkai at all and it could just be like a hedgehog and porcupine situation.