Rift by Andrea Cremer

Long before the world of Nightshade, there was Ember Morrow — a girl born to a destiny she never chose. Bound by oath to a secret order of warriors, Ember must defend against dark forces threatening to consume their realm. But when she meets Barrow Hess, a mysterious knight sworn to protect her, her loyalties begin to waver.

As Ember’s power awakens, she’s torn between duty and desire, between the light she’s sworn to serve and the shadows calling her name. Rift is a captivating tale of courage, forbidden love, and the origins of a war that will shape generations.