Fairies (derog. Imps) are the offspring of humans and Mud Beasts.
Fairies reside somewhere between the physical dimension and that of demons. Some have the ability to traverse the Earth, while there are rumors of fairies having travelled between each dimension at will. The space which fairies occupy is typically a pocket dimension of their own creation.
Unlike Mud Beasts, fairies are not consumed by sin or madness, since they are born with humanoid bodies and are well-adapted to consicousness. Their lifespans are apparently much longer than those of humans. Fairies mostly feed off of life energy and seldom eat. They are also able to sense auras.
While not inherently malicious like Mud Beasts, fairies share the same propensity to fixate on specific, irrational desires and are known to trick humans into satisfying them. Fate, for example, makes misleading pacts with various "contractors" to gather curiosities for his shop.
The blood of fairies is imbued with the same miraculous powers associated with all demons. This is most commonly implemented into sigil work and the creation of relics. Their bodies are humanoid, with some possessing bug-like mutations i.e. chitonous growths or bugs' wings. They also tend to be shorter than the average human by about a foot. Many use their reality-altering abilites to present themselves differently when interacting with humans.
Sometime around the development of cosmopolitan society, the ability for demons and humans to produce children waned, and so fairies are very uncommon. An exposure of humans to electricity and technology may be the impeding factor. Fate, a fairy, has been shown to have a revulsion towards cell phones. The reasons behind this phenomenon are unknown.