………I dont know who to blame here, mr.uke or mr.seme :/

I think it's pretty clear. The seme (crazy guy) is the one to blame.

That's true. Uke did seem to set off a switch for the seme (who possibly might have a mental illness). If someone triggers something precious to someone like that it could cause them to want possession. So it really is hard to blame, I think we should all blame the mental illnesses.