I just started running the Threnal chain.....started the second quest got to the Clay Golems - I am in Old One so figured I would lethte Tentacles do the heavy lifting....I was zerging and figured I could get all the agro before Coyle got himself into the action....but he just up and *poof* died. So I go back in and this time I locked him down right after the mephits and went to the golems with only the defenders in tow.....tentacles down - two defenders dead almost instantly.....so it looks like the Tentacles and NPC's don't mix....but the good part is you can kill Coyle to your hearts content now and that makes me smile.