Well, it all began with imagining a scenario where Tezuka was the fairy instead... A fairy king seducing Fuji away from the human world. And from there it gets really involved, so to actually tell you the idea, I'd better use a PM (I hope that's okay?). But around the point where I'd have to change their names for any of it to make sense, my beta reader, Sumeria, informed me that it had long since crossed the line from "fan fiction" to "original story".