The shadow cloaker is an unusual parasite that is believed to have been spawned on the Demiplane of Shadow. Once it attaches itself to someone, it uses them as a conduit through which it can drain the Constitution of other creatures. If unable to satisfy its hunger in this fashion, it begins to feed directly on the Constitution of its host.
When seen in bright light the shadow cloaker appears to be a black void in the shape of a great cape. Because of its ability to blend naturally into shadows, the cloaker is rarely seen except when it has already attached itself to a host.
It is believed that shadow cloakers are intelligent and may have their own language but every attempt to communicate with them has resulted in failure. Attempts to establish direct mental contact with any form of cloaker often require a madness check.