For A Quick Answer To That. Use Backfire & Empathy. Cast Them Both On Him & Let Him Attack You Till You Down To Half Health. Run Away Regen & Do It Again. He Will Eventually Die. Just Only Bring Empathy & Backfire.
Uh, just equip all you sac skills and dont use them. It's rlly simple. You only start using them once he gets low on health. If you got Awaken take that as well. (dont use it doh) And dodge his arrows.