That is actually something I'm planning to toy with as an antogonist in my changeling game as a throwback to a character my player group dealt with at the end of a hunter game. They made a deal with The Fae Keeper in order to bring one of the player characters back to life (the player was a fetch, and the original changeling had killed him, because you know. reasons) and in exchange the players went and kidnapped a Demon they had encounter in a previous session or two, under the logic that the demon was super good at getting secrets and the Fae modelling himself as a 1930's gangster crimelord...