Soulbound (Legacy of Tril #1)

Tril is a world where Barrons and Healers are Bound to each other: Barrons fight and Healers cure their Barrons' wounds in the ongoing war with the evil Graplar King. Seventeen-year-old Kaya was born a Healer, but she wants to fight. In Tril, and at Shadow Academy, where she is sent to learn to heal, it is against Protocol for Healers to fight. So Kaya must learn in secret. Enter two young men: One charming, rule-following Barron who becomes Bound to Kaya and whose life she must protect at all costs. And one with a mysterious past who seems bent on making Kaya's life as difficult as possible. Kaya asks both to train her, but only one will, and the consequences will change their lives forever.