Devils

Often confused with the idea of demons that arises in some cultures, Devils are godcrafted humanoids that have an impressive amount of godly power within their being. 
While not capable of the grand feats many gods can perform, Devils instead are able to intertwine their being with mortals through esoteric practices that always end with some sort of deal. 
Farther than that description, no one seems to know what the purpose of the Devils is. Or was, as they have long since stopped being beholden to any godly or governmental apparatus. 
They seem to just appear, make their deals, then vanish just as quickly with no goal clearly accomplished or failed. They appear for beggars and kings, and offer all sorts of prizes and rewards that vary from mundane to grand.   
If there is any culture or comradery between different subjects of the species, it has not been seen.