Hmm... dark powers + light powers...?
I suppose he would be some kind of Cecil-type character, where he has a dark mode and a light mode, and in his story he would have to balance out those inner powers. He would be some kind of anti-hero like Alucard. Probably shunned.
Well, as Cornell says "Not all creatures of the night are evil".
Also, yeah you probably should've just said "Salem Witch" which is how I know 'em.