An Endbeing (short for N-dimensional being) is a sapient (except in 2D, under intense debate for 3D) creature that inhabits all universes in The Stack except for E0 and E1 where no life can exist.

Common characteristics

Endbeings don't look very alike, even in the same topology. This is because of their intense sensitivity to radiation which can cause their appearances to spontaneously, drastically, and irreversibly rearrange. An individual appearance is known as a "form". While forms can be almost anything in theory, they almost always fit into one of a few archetypes:

Brachiocrus, a mix of draconic features, human features, and random mutations, with varying numbers of arms and legs
Arraphim, featuring one central eye connected to multiple arrays of wings
Toriphan, featuring one central core polytope surrounded by eye-covered rings; the rings can be spherated circles, spheres, glomes, etc. and vary in many aspects
Symbolacron, one central core polytope surrounded by duoprisms of characters in human writing systems (which were taken from Symbolacron forms, not the other way around)

Reformation

When an Endbeing reforms, their personality and intelligence always stays intact, and their voice tonality is likely (but not guaranteed) to be similar. However, their exact voice will vary a lot since they'll have a completely different arrangement of mouthparts, thus having a completely different set of pronouncable phonemes. Thus, most Endbeing languages have a feature where phonemes are determined by the closest sound to what was actually pronounced, as opposed to human languages where it's more exact. Also, for whatever reason, most Endbeing languages have genetic phonemes, pronounced by manually switching forms, thus having a conversation will often involve swapping rapidly between forms and looking completely different at the end. This has become a bit cumbersome, so there's an increasing movement to substitute these with something else, such as crossing any two appendages or pronouncing something close to the French R sound. Later iterations of the lore have removed the genetic phonemes as they made main characters hard to justify having an actual character design. Reforms are now a lot rare, and essentially happen instead of cancer. So it's about that common from background radiation and significantly riskier up close and personal with radiation.

~~Due to the constant reforms, Endbeings don't typically die of old age or physical injury, but they aren't invulnerable and can die in various ways, most of them equivalent to causes of death on Earth.~~In later iterations of the lore, this is somewhat true, but they need to get reconfigured by radiation in order to heal and can no longer do it manually. There is also a limit of roughly 5000-5500 reconfigurations before the body kind of just crumbles, however this leads into new concepts called cycles and math agents.

In later revisions of the lore, endbeings can no longer generate their own radiation, and don't use reformation as a phoneme in language. The lore gets way too complicated to design otherwise, as every character with a specific appearance needs to have some reason they aren't doing it.

Gallery

Uncovesseltuxe and Outzschcrad's previous form, examples of Brachiocri.
Thaneophyros, an example of an Arraphim, although this image is deconstructed to fit in 2D; everything would actually be connected.
Two examples of Symbolacra (one slice, though it would look mostly the same in other slices).

Trivia

The reforming mechanic was inspired by Doctor Who, though the author does not watch Doctor Who.
The genetic phonemes were added for the possibility of submitting Quatrammotile to a future Cursed Conlang Circus hosted by YouTuber Agma Schwa.