In this quest you if go random brainless dps Zhaitan's eye will bug. No matter how much you try if you attack the Eye for long the Eye will run until it will bug. Buged for me once and for my friends forever. Found a way to do it and its working from 1st try. All you need 2 do is to get Zhaitan's Eye into last phase. That means you have to Melee DPS him so he can ran and get into phase 3 faster.