i watched dead boy detectives this week and now i'm kinda obsessed with making it about thiam. so i present you the thiam dead boy detectives au plot bunnies in my head 🐰
there are different ways i imagined it. the first:
theo dies and is sent to hell. now, contrary to what happened to edwin, he very much deserved it. his hell in this au is similar to his canonical hell, so tara keeps haunting him and clawing his heart out of his chest and then it all starts again – for eternity. but he manages to escape! and he decides to spend his afterlife doing some good deeds so that he can maybe convince death not to send him there again if she ever catches him.
then he meets liam and keeps him company while he slowly dies after being beaten by his teammates. when liam wakes as a ghost, he wants to get revenge, but theo is afraid that's gonna get him sent to hell, and so feels compelled to guide him in a different direction. liam lets it go but decides to follow theo and solve ghost mysteries with him forever :) at first theo doesn't want him around (because vulnerability is a bitch) but liam is as stubborn as he's beautiful, so there's no escape <3
at some point theo will have to tell liam the whole truth about his past and how cruel he was, of course. liam is taken aback, and they have a fight and theo pushes him away in the worst way possible. but then liam is in danger and theo sacrifices himself for him and is dragged to hell, and liam still decides to risk everything to get him back!
alternative that mirrors the teen wolf canon:
liam is a ghost that works together with scott, stiles and the others in the dead boy detectives agency (it was only scott and stiles at first, then other people joined, both dead and alive). they meet theo on a case, but he manipulates liam to obtain something (he could be a witch in this, or an evil ghost, or another type of creature).
at some point, he gets killed (or just caught by death) and sent to hell. years later, when the detectives have to go to hell to retrieve something or someone, liam meets theo down there. theo decides to help him because he feels guilty about everything he's done in the past, and in the end liam can't leave him behind, so he drags him all the way back to earth.
theo has a lot of magical knowledge and decides to use it to help the others solve all their cases, even though they don't trust him. liam doesn't either, not entirely, but he's the only one who saw theo in the depths of hell and is sure that the boy would do anything to keep himself out of there.
theo of course develops a strong sense of loyalty and devotion towards liam, just like in canon <3 and in the end, maybe there's a moment where liam could finally move forward to heaven, but decides to stay behind with theo <3