ha very carefully, he's the toughest fight in game imo but that's because I use a 2h warrior and the blizzard saps my precious stamina. I hear magic and archery help, especially with potions
Is it for a quest or can you just go and kill him?
there's no quest and he's somewhat "hidden" like an easter egg of sorts...you take something from 1 location and bring it to another then he will appear