First referenced:
The Desolate Guardians (Part 6)
Additional references: 'I didn't miss the end of the world (Final part)
Shadow Entities exist on a different plane of existence to the physical plane, apparently independent of the standard multiverse. While their exact nature is unknown, they appear to consume the conscious mind or soul of their victims, and enjoy causing sadistic confusion in their victims. The Shadow Entity encountered by Heath and Noah Fulmer is aware of The Crushing Fist, and has made a deal of sorts with Heath (the terms of which are currently unknown) to help various people working to fight the end of their universes. Other Shadow Entities have also been encountered by Jonathan Cortin dwelling within The Black, these have displayed very hostile intentions through sadistic psychic torture, along with violent dismemberment of anyone caught in the open when The Black arrives.
The Shadow Entities are feared by Dream Stealers. It is likely many varieties of Shadow Entity exist, each with widely varied traits and intentions. The Shadow Entities appear to be connected to The Black, The Ink and the Shadow Sphere.
Terms used:
gwellion - reference to Noah Fulmer, possibly the hunter personality.
ukvwaa - reference to the state of interrogation (drug induced plus shared mental/psychic probing) that Noah Fulmer, Jay, Roger and a number of others were subjected to by an unknown force.
fivhen - comparison to bug
squuar - comparison to mud
vwaal - unknown, possibly a state of being (in as such as life or death is a state of being). Apparently a negative state in which the victim can not be helped. (Also known to Heath's coworkers, although they do not explain what it means).
Traits:
Non-corporeal entity that exists on a non-physical plane. Apparently 'carnivorous', in that they consume or eats sentient minds or souls. While the Shadow Entity encountered by Heath presents an apparently hominid 'front', the overall organism is considerably larger and more complex, but shielded from being accurately described by its very nature. The Shadow Entities encountered by Jonathan Cortin are described as being colossal, with endless snake-like shadow bodies.