Kayne + loss of power + trapped somewhere
Go have fun
I am having fun.
First idea: Kayne's solely lost the ability to teleport. Time travel isn't so useful because now he's flung himself out in space. So he has to walk places. Or get a car.
He explodes a lot of things out of frustration. What are his goals? He's not sure, he's just being annoyed at every little thing. Teleporting is his whole thing and now that bit of freedom is gone.
I suggest he's stuck in Addison. No cars, very snowed in. He's going to have to wait for a car to come in or decide to walk through the ice. The town has long burned down in his frustration. He's picking through the rubble and not even a bicycle (would be terrible in the snow anyway).
So he just sets to walking. First car he finds he explodes the person inside. Fun fact: gross. Kayne has to half-heartedly clean the windshield off. Also car's are incredibly slow (not instaneously).
And yes, of course he could take portals. But have you seen how dangerous they are?? Look at what happened to Shub? And worse, to the King in Yellow? He doesn't want to have a fragment of himself running around making friendship bracelets and calling himself Stuart.
Second Idea: I'm shoving him in an unlocked closet. He's a little completely unused to getting out of places without teleporting and not thinking the best, understandable really. So he just panics for an hour or so before sheepishly finds that he can twist the knob.
I propose he shows up at Arthur's home, Arthur realizes he has no powers and shoved him in there. Just to see what he can do. He doesn't even put a broom in front of it because Kayne is already so panicked from it.
He's making tea in the other room, discussing nothing much with John when Kayne finally stumbles out. Let's call it establishing the pecking order (though Kayne would probably nearly die just to spite another person. So basically a two Arthurs living together situation).
Third idea: This is after the last season. Everyone could kill him, but is agreeing that would unfortunately be for the worst. However, Kayne still has an awful habit of ruining people's plans and trying to kill them (still has a ton of occult knowledge). So there's a rotating schedule on who has to deal with him between the Manager, Lillith, and Arthur.
Arthur somehow ends up getting the most frequent and longest shifts (he's going to die soon so he has to pull his weight to make up for it). And everyone has independtly decided they are just shoving him somewhere until it's the next person's turn.
Arthur gets the fewest escape attempts (Kayne actually likes Arthur and he knows how to escape occult things, not ropes). When he does manage to get out of the closet/unbound/out of that coffin/unbound from magical restraints/usually a combination of everything they can think of to throw at him, he's very upset. And just walks up to them, attempts to kill them and proceeds to get trapped again.
Occasionally he has some nice conversations with Arthur before being shoved back in the closet. He's still tied up though. Arthur's trying to rehabilitate him or something.
