I’ve been thinking about ???% a bit lately so now I just have this disconnected scenario/AU/headcanons where it’s this powerful spirit that befriended Mob as a child and subtly possessed him, like Dimple did with Ritsu, so Unkown could slowly hone Mob into the perfect vessel. Except the plan backfired b/c now Unkown really cares about this poor kid and knows it Fucked Up by accidently hurting Ritsu, so now it’s more of a guardian spirit/psychic backup generator for him.
I really like the idea of Unknown physically crawling out of Mob horror movie-style the first time it leaves his vessel since it’s been inside Mob for like, ten years, so now it’s almost a part of him (it’s still safe for it to leave tho, Mob just gets a little dizzy afterwards and the depossession gets less extreme over time). I imagine it’d be forced to come out during an event where Mob’s chance of dying is Very High and there’s no way in hell Mob’ll be persuaded/is physically capable of taking care of the problem himself. Obviously Ritsu and Teru are very nervous around it (and Mob was convinced it was just an imaginary friend he used to have), but ???% gives them space and tries to make it clear it was sorry for hurting them. No one really fully trusts it except Mob in the end.
???% can’t speak (at least not any human language), so it primarily writes things down and draws diagrams. When asked who/what it is, ???% just writes the word “protection” so Mob and Ritsu start referring to it as Hogo instead of “that thing” or “the spirit.”