We could blend both those ideas into one. We just have to figure out what his secret might be. Magic powers in a world where magic is forbidden/doesn't exist? Or just a forbidden brand of it like dark magic? He could have a mark on him that gives away what he's meddling in... Or he could be a non-human living in a human world?

Well, at least I have someone to share my plague with now. Misery does love company, after all.