Uldor is an undead Maormer wizard on the island of Khenarthi's Roost. He is the main antagonist of the Tears of the Two Moons quest and is currently in possession of Rurelion. Uldor has been shown to be able to "wear" the bodies of other beings. He has exhibited this ability on Rurelion and Gathwen. He refuses to wear the Vestige's form, calling it poisonous and soiled attire. This could be because he recognized the Vestige as a soul shriven.
Uldor has taken control of Rurelion and many other people. The Vestige has to defeat Uldor to free them. The Vestige has the option to either seal Rurelion or Gathwen inside the tomb while Uldor is possessing them. Once the Vestige places the Mourning Stones on the pedestals, he will be trapped in the tomb.