Uldreiyn was an Elder of Starym House and a former archmage at the Coronal's court. He was also one of the most influential members of his house, using his experience to guide his fellows in difficult times. Like all in his house, Uldreiyn was hotly against the Opening promised by Coronal Eltargrim but knew that direct opposition was futile. When the Lord Speaker of the Starym, Llombaerth Starym, died trying to stop the raising of the mythal, Uldreiyn recommended caution and to surrender to the coronal's will.
But in secret he had other plans, and with his ethereal body Uldreiyn observed the raising of the mythal and soon conceived a plan to corrupt it, to cause it to kill all non-pure-blooded elves inside Myth Drannor. To do this, he secretly killed and replaced Aulathar Orbryn in the mythal's circle.