I camped this guy tonight. The spawn rate is about 35 mins. I killed 2 Goblin Evokers, and a Goblin Prelat. He spawns on top of a small mound in room #4 on allakazam map, at about location 400 by 200. Dropped pack on first kill, thank god I was so bored.
Andujak
Wizard of the 56th