A Plague of Angels — Sheri S. Tepper

Atop a twisting, canyon-climbing road, a witch lurks in a fortress built strong to keep out dragons and ogres. In another part of the countryside, a young orphan is maturing into a beautiful woman in the enchanted village that is her home. Somewhere nearby, a young man is seeking adventure after running away from his family's small farm. Suddenly a strange and terrible prophecy sets off a chain of events that will bring these three together in the heroic, romantic, and thrilling tale of an age-old battle.