The Upphafi

Some humans tell of wraiths in the night to scare their kids, but the Dwarves weave tails of the Mysli, a demon of shadow that haunts the dream of restless sleepers and the injured, usually it's used as a tactic to keep youngsters out of harm. From what's collected from the tales it acted as a spy of the Everdark, infecting the minds of creatures to fight as fodder of the demons, It is said to manifest as a pitch black storm cloud, billowing above the victim(s).

Summary

A smoke demon that infects the mind of creatures/Humanoid

Historical Basis

Back at the beginning of the 2nd Celestial War the Everdark used them as spies, hidden away in the Sandstone Mountains the dwarves came across a stone tablet imbedded in the wall of a cavern, It spread the entire wall (50 meters by 100 meters) written in Celestial, once translated in reads, "Beware the smoke, whether fire or not, they come from every direction and plagues my essence, we can't trust anyone, Mortis has betrayed us already, if he's gone insane no one stands a chance. Hidden in this hill is my relic, if you want any chance of victory you must collect it from the depths of the hill."