A Grand Battle

Username: Oh wait oops nope
Name: Somn
Gender: N/A
Race: Nightmare
Colour: 33101E
Description: Somn is an incorporeal, intangible ghost until he finds someone or something asleep. He then takes whatever form their nightmares consist of, although his personal flair to any form consists of concealed extra limbs, the smell of stale earth, and a nearly-inaudible noise coming from no particular direction while he is near.
Items/Abilities: Somn is normally tethered to his host of choice, but with sufficient cultivation of his host can begin to mould their dream into a form that better suits him, or gives him more useful capabilities. The host cannot wake up through normal means, but killing them will effectively incapacitate Somn. It finds this highly unpleasant, but has the means to protect its host.
Somn can dematerialise and reappear at will at its host's side if it perceives a threat, and for especially susceptible hosts can manipulate their thoughts into sleep-walking.
Background: Somn is a relatively rare monster from a modernish age with something of a hangover from its high-ish fantasy roots. It takes little interest in most affairs, other than those its perceives as a threat to its existence. These it'll have die in messy ways, if it can't just straight-up catch them when they're sleeping. Malicious by nature, but also cunning in a self-preservative kind of way.