I think you've got it. Make it personal. And make him enjoy making it personal.
Of all the books I've read, I think the antagonist I hated the most was a man whom you don't realize at first is a bad guy. He's a man of sterling reputation. Everyone admires him, emulates him, wants to follow him. He's the hero everyone's been waiting for--a brilliant warrior, handsome, highly intelligent, yet self-sacrificing and humble. Except he's not. And when, through first one action and then another, the facade starts peeling off, you are at first stunned then horrified to learn what he really is underneath and to what lengths he will go to destroy the character you care about the most. This bad guy, you realize, is not just bad, he's entirely without conscience, scruples, morals, or ethics. Like Satan, he appears as an angel of light and is completely evil. And you hate him so very much, and meanwhile you suffer, because he seems indestructible, and he attacks the real hero in the most personal and cruel ways imaginable.
So maybe your bad guy could be a little like that.
I agree with this. The worst kind of people to me are the ones that present themselves as the heroes who are actually self-serving, manipulative monsters. I'm doing this in my WIP. Interestingly, my inspiration centers around the fall of Lucifer, only in my story the fallen one is the actual good guy and the "God" character is the villain. Which I know isn't anything new, but it's a trope that's close to my heart.
Self-righteous hypocrites are what I loathe the most. So that's what my villain is.