A serial killer.
Let's assume it's a man. Let's assume he lived his childhood, grew up, went to parties, fucked all the women he pleased because of his badass nature. He floated through school just easily enough to claim it was natural. He leads a good life. Maybe he's just like you, or maybe he's just like me.
Let's assume he, at some point or another, thinks he has a "better" or "more pure" worldview than you or me. I mean, everyone has these fleeting thoughts now and then, over little things like disagreeing with Sharia Law or the Holocaust. But really, what separates your dislike for these ideals from his hatred for ideals like socialism and (what he sees to be) false worship?
Maybe what separates him from you or me is his conviction. His willpower, his fucking balls. The fact that he's willing to go so far as to carry the 11th Rule to the fullest extent. He won't allow another to stand in his way, he'll do what he needs to to crush his opposition.
All that separates a serial killer from you or me is that he will stand for what he believes in, probably more than we ever would.