I think Vorbis is worse for me because he's not just doing things for the sake of doing them, he thinks what he's doing is right. He may not believe in Om but he does seem to believe in the church and his place in it. Plus, cruelty to animals, I mean come on.
Mr. Teatime is on the same level as Carcer, too. Pratchett was so good at writing evil characters who are simply doing their thing with no self-awareness. No guilt. No consideration. Blithely non-empathetic.
I think Mr Tulip wins for me. The art stuff, the -ing and his "drug" habit slay me. And I kind of feel bad for him despite his psychopathic murderous tendencies.
Dios. What a dark figure saddled with a dark fate. He's basically cursed to live the same life over and over again, no wonder he's insane. I think the implication is that he created all the Djelibeybian gods, and the reason these gods existed at all were because they were the ones that were always recreated by Dios. His staff of a snake eating its own tail is apt.
The Hiver hands down
Like... basically an entity of nundualistic evolution through the ages. Tiffany turned manic when possessed and the little "help me" is also relatable