Dropped by "The Fabled Skeletal Berserker" in the courtyard next to the steps that lead upstairs in the back. However, as we QUICKLY found out, (By stumbling on him about 30 seconds after we killed him), he can spawn anywhere a Skeletal Berserker spawns.
This guy was pretty easy. Mostly slowable with chanty slow, hit for 500ish. (I think the tank took less dmg than me, afterall, enchanters can only wear silk :P). Our clerics didnt even break a sweat with this mob. Got 3 of them last night, while humorously watching a group of about 12 attempting to take the Drolvarg Warlord.