Thornboldt Durst was the son of Gustav and Elisabeth Durst.

He and his sister were locked in the attic by their parents to “protect them from the monster in the basement” (in actuality to keep them from discovering their parents’ cult). They were neglected and both died. Illusions of them remained outside the Death House and if their remains were disturbed, they would come back as ghosts. The only way to put them to rest was to put their remains into their graves.