Derelich

Dereliches are evil beings that inhabit abandoned buildings or parts of buildings. They try to lure people into their clutches by making the building appear inhabited and welcoming and, once the poor victim is within their grasp, then kill them. Somehow the deaths of their victims provides sustenance to the Derelich.

There is never more than a single Derelich in a small building, though wings of a large building may accommodate one each. Even then, each Derelich keeps to its own area, and they seem to ignore one another. However, a Derelich can manifest in a large number of spirits, up to 24 in most cases, each of which can take the form of any living creature, playing a role in the charade of the building and playing a role in the attack. These fragments can leave the building, but they cannot go very far; no more than one yard from the edge of the building’s plot, usually.

The Derelich can also change the appearance of its building, inside and out, making it appear as it was at its height. This makes holes in floors invisible but doesn’t actually repair dangerously damaged buildings.

Whilst Dereliches are spirits, they do not appear to be Undead nor do they seem to be Chaos Daemons. Their natures are something of a mystery, and in most of the Old World, they are hardly ever seen. They are, however, quite common in Aquitaine, Bretonnia.

Source

 * Warhammer Fantasy RPG 2nd ED -- Knights of the Grail (pg. 48).