i just did Kaon on HM last nite. the Mercs casued alot of problems, but then once we figured out that if u CC one and kill the other ASAP (assuming there are 2 in mob) and interrupt "constrict" ("The Merc stun is interruptable, if you have no interrupts or it's on cd, you can stop it through knockbacks or stuns." this isnt true i was interuppting them all the time) they arent too much an issue, and besdes its called HARD mode for a reason. the bloated guys were more annoying than the Mers (in my opinion), if they pop near yer healer or in your party, its almost certain you are going to wipe.

its HK.. THE HK, he is like 300+ years old and was re-programmed/upgraded by Malgus... he is NOT gonna be easy to kill, and is not easy to kill.