Demon is the third book in the Gaean Trilogy.
Gaea, the world and goddess, has gone insane; she kidnaps the son of the witch Robin. Cirocco Jones and the Titanides set out in search of him into a headlong confrontation with the monstrous power of Gaea.
Demon is … a novel that’s packed full of individual moments and scenes that stack up to the best writing Varley’s done. He seems incapable of creating a character without a complex motivation or an interaction without a complex sociological background, but he explains everything simply and smoothly, with a minimum of wasteful padding. These are Great Big Books in the best sense–grand, almost space-operatic yarns from the days before it was necessary to write a thousand-page epic to tell an epic-sized story.