@chain
I can't quite tell if he's straight up a socio/psychopath and finds it entertaining to be an actor or if he actually has genuine, albeit twisted, feelings.
My personal hypothesis is that Douma has his own version of emotions, but two functional factors cause them to be shallow: He cannot truly care about anything outside himself, and he's so confident he can't imagine anything INSIDE himself being actually threatened. Inosuke and Kanao can feel intense rage because a person precious to them was destroyed. But Douma's favorite person and his favorite bookmark probably mean about the same to him.
Douma probably doesn't think he's missing anything in terms of feelings -- but that's because, like gods and buddhas, he regards feelings deeper than his own as things that obviously don't exist, that only stupid people would believe exist.