Heritage of the Xandim (Chronicles of the Xandim, #1)

This series returns to the lands of Aurian, and is set in the distant past of the Magefolk, when even the land was a different shape, and the sea between the northlands and the south did not exist.
This was the time when the Artefacts of Power were created, and lives were torn apart by the Mage Wars.
In those days, the Magefolk were comprised of four disparate races: the human Wizards, masters of earth magic; the winged Skyfolk, who controlled the magic of air; the Leviathan, who ruled the powers of the watery realms; and the great Dragonfolk, whose province was the magic of fire.
But while the four races of the Magefolk strove and vied amongst themselves to master the powers of magic both good and evil, a new race was emerging, who would come to play a vital part in these phenomenal events.
As the story opens, the Xandim are little more than simple beasts. Enslaved by the fey and powerful Phaerie, masters of the Old Magic, they have been trapped in their horse forms for so long that they have forgotten they once held a human shape.
Only one of the tribe knows better: the Windeye, the shaman of the Xandim. This is the story of his epic quest to free his people.