I killed the Priestess and received this neck item.
She is a Wizard, green to 51. Her melee was max 51, and her DD's were Cold for 200 max and fire for 150 max. She is easier than Cynthia in Rathe Mts, so I would estimate her level to be about 25 to 30.
She dropped both this neclace and an earring (Terafol's Earring), in 2 seperate kills, I was unable to get another shot at her because I ran out of time, so I cant tell you if this is her rare or common.
Faction loss with Priests of Life, and Qeynos No Faction gain for killing her.