The Death House is the home of Rose and Thorn in the village of Barovia. It’s clearly haunted in some form or fashion, and was home to some cannibalistic cultists in the past.

Gustav and Elizabeth Durst, the parents of Rose and Thorn, had attempted to summon a demon to grant everlasting life, and had pleaded with Strahd von Zarovich to intervene. Strahd had refused via a letter. Due to their cannibalistic natures, Gustav and Elizabeth became Ghasts while many of their fellow cultists became ghouls. Baby Walter’s stillborn corpse was transformed or added or somehow conjoined with a monstrous undead creature that consisted of most of the bones of those sacrificed by the Dursts.