First Appearance: Doctor Strange (vol. 2) #53 (June 1982): "Land of the Pharaohs"
Super? (Has Super Powers/Special Abilities/Technology): Yes
Number of Appearances: 1
Enemy of: Nightmare
Note: personal nightmare of the demon Nightmare
Gnit is the "personal nightmare" of the recurring Doctor Strange villain Nightmare. There is some irony in this (no doubt intentional) because Nightmare himself is a demon who invades and manipulates the nightmares of mortals.
Marvel's website (http://www.marvel.com/universe/Demons) classified Gnit as a demon.
Gnit first appeared in Doctor Strange (vol. 2) #53, and this remains the character's only appearance. This first appearance was apparently the Doctor Strange #53 that was published in June 1982 as part of the second "Doctor Strange" series. Interestingly enough, Nightmare was also the featured villain in Doctor Strange, Sorcerer Supreme #53, which was published in May 1993. But I believe that this 1993 comic is NOT the story in which Gnit first appeared.
Suggested links for further research about this character and the character's religious affiliation: