There's a non-canon of TK-0 i think about a lot, that involves like.. a bunch of other non-canons at once so I won't go super into detail but the basic gist is that there's another TK-0 (called Holen't - not in character, but when we're talking about him for ease) who's torturing another ko (owned by @bubbleberryuniverse) and the nice TK-0 is trying to stop it and it ends up with him being demonfied, separated from his K-0, stuck in a dirty, stinky, bloodstained old basement covered in spikes that his body created out of stress and I just. I love him, he's a good boy but he is basically feral at this point.
He looks like this! And at one point he manages to escape, go to hell, and eventually get back home and he just.. he straight up decides the bathtub is his home now. He refuses to exist in the same room as Holen't (he WILL bite Holen't if he enters the bathroom, Holen't is actually banned from it because one time he went in and ended up almost getting his arm torn off.) and he's just. a good boy.