Also, here's something from the movie Forbidden Zone, which I stil maintain is one of the best/most unconventional modern tales of the Fae out there, that you could flat-out reuse in a different context.

When Squeezit goes to the Sixth Dimension to save Frenchie and his crossdressing brother Rene from the bitter and jealous Queen Doris, he gets captured by the Devil's minions and taken to his lair. The Devil, played by Danny Elfman (No, really), does an AWESOME song & dance number to the tune of "Minnie the Moocher" about how he's going to cut of Squeezit's head.

But when Squeezit tells him of his plight, he says that if Squeezit captures and brings him the topless Princess of the 6th Dimension (it makes slightly more sense in context). So Squeezit does so, and when he brings her to him, the Devil says that he'll keep his word (Which we find out later in the film, he actually does), but he'll also keep his word on cutting of Squeezit's head. Which he does.

While Squeezit does survive as a disembodied flying head on chicken wings, this scene adapted to your game would be perfect for illustrating the fickleness of the fae. Also, from my description of that scene, can you guyess why I love that movie so very much?