I killed him this weekend with a 69 Shammy, 59 SK, 67 cleric, and 58 Monk. That was ubah overkill. Just my monk and a cleric would have been enough.
Zhaoku spawns immediately after the crusader recieves the stupendous tome and the crusaders coffin. He spawns correctly identified in the zone corner between the wall and the seb wall. He IS slowable. He has a lot of hps, but doesn't hit terribly bad. Max was like 220. But slowed he's a wuss. He did enrage around 15%, which was the only time he really did any damage to us. He dropped the bones I need for the whistling fists (all I need is fallen monk now and turn in to CT). He also dropped mage spell Aegis of Ro.