The Dead Lands of Athas
A raaig is a guardian of an ancient temple or shrine devoted to a long-lost god or religion. It allows those with similar beliefs to enter their temple, usually a grotto, stone building, or underground complex. The raaig warns any trespasser that enters its guarded area, often in an ancient language or through signs the raaig considers clear. If the warning goes unheeded, the raaig attacks swiftly.
Raaigs appear as ghostly versions of their living selves. They are usually dressed as priests or warriors in the clothing or their old religion. They can take corporeal form and do so when attacking. Raaigs were created millennia ago to protect temples or religious grounds. Though no ritual is known, some raaigs have the ability to create other raaigs, but only if the creature is willing to become one.