He was first killed on Nova, a few hours after Summer Update 2008 was launched. After killing the upstairs section of the Northeast room (All 3 warlocks), he will spawn 2 warlocks (Not summon) and then spawn himself (so he can summon green djinns) See the following video: https://www.youtube.com/watch?v=JhhKJZWLwMg
Melee (0-130), Burst Arrows (0-250) fire damage, Fire Fields explosion shaped, Heavy Magic Missile (0-250) physical damage, Great Energy Beam (130-350), Mana Drain (0-250?), Paralysis, Invisibility, Self-Healing, summons 0-2 Warlock, summons 0-3 Green Djinn.
Damage Taken From Elements
Demona, in the room Northeast of the pentagram room.
Zarabustor behaves same as a normal Warlock.
Trap him in the corner and kill him like a Warlock.