Cry of the Marwing: Book 3 of The Kira Chronicles

The mare snorted, wild-eyed, and danced sideways as a dark shape launched itself at Kira, knocking her off her feet. It leapt on top of her, then a disfigured face thrust close, its lips drawing back in a macabre smile as hands tightened around her throat. With battles raging and Shargh warriors threatening the future of Allogrenia, gold-eyed Kira is forced to betray her every principle by requesting Tremen Protectors fight and kill to defend their homeland. As the sickening carnage continues, Ashmiri treachery threatens to deliver Shargh victory. Realising her love of Tierken is not enough to bridge the gulf between them and their respective people, Kira flees Terak. Reunited with Caledon, her companion of yore, Kira decides to make for her Tremen homeland. But as she and Caledon approach Allogrenia, Caledon's star vision fails him and they're confronted by Shargh.