Alright, second run through Drezen has gone very well so far, a lot more efficient than last time and even cleared the unhittable demon with infinite spell resistance in the tavern, even though my entire frontline got downed (and Nenio who I tried to use as a tank with mirror image to buy time flat out died). Now almost the entire outer section is clear, just got this Mad Kellid left.
What's the best way to take him down? Don't say grease because he's obviously going to save.