Rosavalda and Thornboldt Durst are siblings, a ten-year old girl (Rose) and her seven-year old brother (Thorn). And they’re definitely weird.

One version of them existed outside of the Death House and convinced the party to go inside and save their brother Walter, look for their parents Gustav and Elizabeth, and defeat the “monster” in the basement.

Another version of the children were ghosts. Their dead bodies were found in a children’s room, locked from the outside, in the attic inside the house. The ghostly version of Rose tells the players that they have been dead many hundreds of moons.

Rose possessed Yenkin, and Thorn possessed Brume when the party tried to leave the children’s room, out of a desperation to not be alone again. When Yenkin died, the possession was severed and Rose, until he later rested in the children’s room again and became repossessed.

It was later found out that her parents were attempting to be cultists to summon a demon to grant them everlasting life, and had pleaded with Strahd von Zarovich to intervene when they failed. 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.

Both of their bones were laid to rest in the family crypts. Thorn vanished, but Rose continued to hang around until she was finally able to meet a procession of ghosts at midnight near the Church of the Sun.