I don’t remember if I ever posted this, if I have then dang it I’m doing it again!
So when I was fresh to the Undertale fandom I had a lot of fun learning about the multiverse and I loved the implications it has like the common question of “is there other multiverses?”, I didn’t think much about this question until my brother brought it up. And boy howdy did it disturbed me. It took me a while to swallow my pride and agree with him the the notion of multiple multiverse not only destroys the purpose of a multiverse but (in my opinion) makes things to redundant, also if there are multiple multiverses then there should be multiple of those multiple multiverses and on and on. There’s not much room for the player themself to be presented as the ultimate threat when the world already has much bigger fish.
I made this diagram thingy that explains how I imagine the multiverse (at least mine) and others can use to change or add on to.
The diagram thingy above shows the multiverse as its whole. In my story, canonically, no one actually knows what the multiverse looks like or if it even has a shape at all, any and all diagrams or depictions are solely theoretical (including this one). This depiction of what the multiverse could look like, also knows as the “World Tree Theory” is what is taught to new travelers and in multiversal schools because it’s the best at explaining the multiverse as a whole and its behavior.
Unimportant side note: when I look at shows that features a multiverse (marvel) its done more from an evolutionary standpoint witch can have some really interesting worlds, cuz evolution doesn’t care about rules it cares about survival essentially allowing you to make whatever world you want. In my story it’s going to be more focused on creationism cuz for one its my belief, two I think it would be more interesting morally, and three one of the themes is asking the question ‘what is a god?’ or ‘what makes someone a god?’. This idea came from the fact that there are some pretty strong characters that can do some pretty insane things and perhaps in their life were worshipped and treated like a god, but are they a god? If so what makes them a god?
ATs are described as the “veins” of the World Tree and are the most common type of world sense every Alternate Universe has ATs each typically falling into one of three categories: Pacifist, Neutral, and Genocide. ATs are not alternate worlds in themselves but are rather the different choices we make or more often the ‘player’ makes. ATs can take place in a different time like Undertale Yellow or Horrortale, or in a different setting like Outertale, so long as the characters or the overall main story doesn’t change. Relatively speaking, traveling through timelines is the most simplest way to get around the multiverse although it’s very time consuming on the account you could only access certain universes through certain timelines.
AUs are the “branches” of the World Tree and are the second most common world and unlike ATs, AUs can have the same characters but different personalities/roles like in Underswap, different/new characters like in Glitchtale, or an entirely new story like in Deltarune. Traveling through AUs is the most effective way to get around the multiverse but in order to do so one would need a VARY powerful machine or know someone who has the ability.
I don’t know where to add this but worlds like SwapDisbelief are ATs of there original AU (UnderSwap in this case)
Pocket Dimension are the “leaves” of the AU there attached to and unlike the AUs or ATs instead of being the change in history it’s defined as the change in physics most AUs have the same basic Pocket Dimensions that helps there world properly function (Mirror, Shadow, Light, Gravity, and Space). Comparatively speaking, it’s more easier to fall into a Pocket Dimension by accident than to jump a timeline intentionally and if you do happen to fall into a Pocket Dimension it’s vary important to understand which Pocket Dimension your in because that can determine if you’ll live to tell the tale or die a horrible death. Canonically in my story, Pocket Dimensions (heck dimensions in general) are a newly discovered concept. This discovery fist took place when a scientist discovered that the Anti-Void he was in wasn’t an infinite space but rather a dome (Underevent reference) that acts infinite and separates the Void from the Anti-Void. The Anti-Void is the only confirmed Dimension.
Ok so extra explanation, remember how I said I wanted this world to be more creation based? Well I ment that literally. The idea I had when I first thought of this came from my anger that no one is using dimensions anymore plus I was watching Star Vs. The Forces Of Evil at the time and then it kinda hit me that AUs can the the change in history while Dimensions can be the change in physics, like changing how the world works. I didn’t refined this idea until I took a 3D Animation class and that’s where it hit me again. When you began a project, any media, you start off with a blank canvas, an empty space, a void, an Anti-Void :) (The Space pocket dimension and the Anti-Void is the same thing). Then you’d make a sean or characters and establish its Gravity, add Shadows (Not official yet but the Darkworld from Deltarune and the Shadow pocket dimension are the same), add Lights, and if your felling fancy add reflections. The number of dimensions depends on the medium and how rendered the world is.
Alternate Dimensions - AD and Miniverses
ADs are the “rings” of the World Tree. Whenever the multiverse as a whole takes a different path mainly involves the guardians and the protectors of the multiverse like in DreamSwap or AccidentVerse.
Miniverses are like “knots” in the World Tree and happens when the entirety of the multiverse exists on the same plane of existence and typically doesn’t have ATs or AUs attached to them. Canonically, no one knows the existence of ADs or Miniverses, except of maybe Ink? Possibly Error?
A bit more info: As I said before I don’t like the idea of multiple multiverses and instead think we should adopt to using the term and idea of dimensions instead, also worlds that do fusions or worlds that are like Undertoad or Toontale aren’t cannon in my Dimension but who’s to say if there not in a different Dimension? And if that’s the case then a VARY powerful traveler or someone who just so happens to be in the right place at the right time who can also pass the Firewall could technically travel to worlds outside of the Undertale multiverse entirely. And THATS where you’d get other multiverses >:]