In attempting to get Instant Karma, I died a few times on my Wizard then gave up figuring I was too low level to tank incidental damage, though I did get close (12/15). My major problem was trying to get him to teleport near his minions so he would flail about and knock them to pieces.
His teleport sometimes seems to follow the path his ghostly essence is moving as he casts it—I was thinking it was essentially an invisible straight-line charge—but other times he goes way off and pops out right on me. Does he commit to landing at a certain spot before the effect appears (can't move very far to reposition between that and him popping out)? Is there a range limit/angular limit to it I can abuse?