Spawns in the outside garden area of RT near the zoneline of Pilars. There are two roaming PH's. His aoe has a gravity flux / push to it, so you'll want the entire group in a corner, all on top of each other for this one.
He dropped an Embellished Headdress of Kolos. I used a 95 cleric/bard/sk and a merc tank/rogue/healer. Because of the push, I suggest using the little tomb in the middle of the atrium at the zone line to Pillars. I have done some of the tasks for Resplendent Temple, and the Nitore mobs con amiable, as does Groundskeeper so he is not kos until attacked. The peacekeeper guards outside the tomb will assist, as well as the other groundskeeper spawn if he's up and close by, so be sure they're dead before pulling him into the tomb.