The +5157, +326, -89 position matches up to where he spawned for me.
If you spawn PoValor & Aerin Dar via the Agent of Change, you only get a single set of mobs down below. They don't respawn in the instanced version of Valor. In the regular version, they have a 16m20s respawn time. I ended up parking a coth mage down there to assist in gaining access to that part of the zone again without having to wait for Aerin Dar.