The magic skills, of course. Mostly focusing on Destruction, Conjuration, Mysticism (if they had it, which they don't :/) and Alteration.
I don't see him much into illusion (he doesn't see/care about other people) or Enchanting (he would use it, but it's not his main focus or anything). Unarmoured would be good too, if it was in the game. Instead, just get the unarmoured perks of Alteration
