where in the world is carmen san diego?

Okay just kidding. but I am looking for a very elusive great fairy. I've been to three (Gerudo, kakariko, and in the northwest) But can't seem to find this last one.. I would just look it up, but I don't want to just get the answer that easily you know? So I was hoping somebody could point me in the direction of the sidequest associated with the fairy or maybe just provide a helpful hint, preferrably one that rhymes. :) thanks!