ok so the premise of this au is that the timeline is collapsing, idk how rn it was caused by frisk everyone has fallen to the void except frisk and sans, however, sans got the capsule the justice soul was in before it fell to the void, and he would use it if things went wrong. both sans and frisk are decaying from the timeline collapse, however, frisk can withstand it longer, as they are more determined to stay alive. Knowing frisk has doomed everything and everyone, sans vows to kill the human out of pure vengeance, even though it wont fix what has happened (maybe idk). The fight occurs in a collapsing judgement hall. Thoughts? I might call it Undertale: Vengeance or Undertale: Timeline Collapse
I might make some sprites for it but actaully making a game of this seems too big for what I have in mind
