Help! Mission: Renegade Necromancer

Ok first up i'm a lvl 14 N/R

I've obtained a quest in Yak's Bend to eleminate said renegade necro but upon finding him, he just stands there and doesn't fight back. A minute or two of my party banging on him, he falls over dead without a single counter attack. My quest doesn't update and I am at a loss of what to do.

Any one else had this quest and completed it? I don't usually go for spoilers but this is getting frustrating =(

any help would be appreciated

Run straight up to him and he will boast, it will update your quest (did for me) no need to kill him.

BTW, he is extremely killable as well. I took him out at lvl 12 with 5 henchman. But killing never updated for me.