The Master Wizard in a fort north of the Ritual Stone.
By the time I wandered into the room, my battlemage was skilled in destruction, restoration, and one-handed.
Well, I walk into a flurry of fire mages, ice mages, and the Master Wizard, who just so happens to be a Frost mage equipped with a Staff of Chain Lightening.
I actually retreated to the room prior to this one and stood in the doorway. The mages had to come around a corner to get at me, so I killed them off one by one until the Master was left. And he did not come near the stairway at all. In fact, I could hear him taunting me in the next room.
As soon as he sees me, that staff comes out along with ... Frost storm I believe it's called.
I slowed time, and sprinted up to him and introduced my Dawnbreaker to his face. Once time came back to speed, that damned Chain lightening popped back up. It was a close call, but with my adept level healing and my potions, I was able to stagger him enough times until he died.