He is snarable, does summon. Could not cure the "vicious wound" with purified blood, RGC, corruption cures, or RC. It hit over and over on the pally we had tanking, so a little extra healing was required.
Can spawn from any of the 5 golem locations. Of the 5 or so times I've killed him I have only seen one armor essence, one Tempered Crystal Knuckles, a couple of the pendants, and one of the type-3 versions of the pendant.
Just know whoever pulls him will get hit with "Vicious Wound" and take about 2400 damage a tick as they come back to camp.....from then on, whoever has aggro will be the only one to get hit with it.