The Healer's Rune: Book One of the Ceryn Roh Saga by Lauricia Matuska

Three hundred years after a great war shattered the Council of Races, the warrior Rüddan have all but eradicated their cousins, the faerie Aethel. In so doing, they decimated the Dryht sages and enslaved mortal Humanity. In order to save her people from being wiped out by the Rüddan, Sabine, a Human healer, must overcome generations of bitterness, suspicion, and fear incited by a betrayal centuries old and forge an alliance among enemy races. But what chance does she have when one of those races is extinct?