I am struggling with this. There are two aspects to this. One is an outright villain who commits atrocities without any heed to the effect on others and another who knows that he is harming others and who still does it. But what if the latter thinks it is for the good of the other person? And the other one does not know, cannot know. I have been like that. My father has been like that. Ha! The shame! The shame! This is the character that I am trying to write. Yet it feels like the first one is more villainous because the second one can still be dealt with. But you cannot deal with the first kind. That kind has to be destroyed. But then sometimes the second one becomes so hard that he starts resembling the first kind. Yes, that is the kind of a cruel character that I am trying to write.
So, we start with this one being a nice person and then we see his villainy. The devil lies in the details. Anyone with any insights about writing evil characters? @Llyralen definitely expect something from you here. @PsychReviews ?