In episode 3 of The Haunting of Hill House Luke uses a dumbwaiter to explore the property, with Theo's assistance. After a mishap with the dumbwaiter buttons Luke is lowered to an uncharted basement and is attacked by a ghoul.
Most of the ghosts the Crain family encounter are explained later as former residents of Hill House, such as Hazel Hill, Poppy Hill, or William Hill as notable examples. The ghoul does not seem to be named, and further investigation of the basement by both Theo and Hugh reveal no identity.
Which Hill family member was the ghoul in the basement? Is it an unnamed House resident or somebody who could be identified?