The prequel (though best if read after) to the excellent [book: The Anvil of the World]. Gard is a foundling raised by the remnants of a pacifistic enslaved race. When the race's Messiah comes to save them, Gard rejects his pacifism and is exiled. Dread mages trapped under a mountain for generations catch him, and he begins to realize he has gifts beyond those of his adopted people.
Meanwhile, the Messiah and his successor are not having an easy time themselves.
This is the second of Kage Baker's series, and possibly better than her first, the Company. Good, evil, compassion, nature v nurture--they are all in here, floating in a complex world with believable characters.