The Wight Ending is an ending in Prisoners of the Elder One. It occurs after using the Transfigurative Orb on Valda. It does not work if she is preoccupied with her reflection.
The magic hits a dark barrier and backfires onto Erik, who turns into a Wight, an upperclass undead with control over other unlife. Valda twists Erik's mind to match her ghastly body, and she becomes a student under Valda, now named Drouivah. Later, Tiffany is 'rescued' by being turned into a lesser undead; neither Valda nor Drouivah find any problem with this.