Unbound - Penelope Bloom

Nineteen-year-old Nessa Thorne expects death when she volunteers for the Empire's selection. Instead, she's thrust into Confluence Academy, where students harness elemental magic and bond powerful beasts, from wolves to ancient dragons. Students are branded by affinity: water, air, earth, or fire. But Nessa's mark is different. A silver spiral - the mark of an unbound. It's a power so dangerous her kind were hunted to extinction centuries ago - or so the Empire claims. To survive, she must hide what she is in a castle where alliances are forged in blood and students kill each other freely for advantage. Nessa's greatest threat may be the only other volunteer, Raith Hollow, a powerful fire affinity with a scorching gaze that follows her every move and secrets that could topple kingdoms. Forbidden desires become impossible to ignore, enemies approach from beyond the castle walls, and something evil has found its way inside - stalking the midnight corridors, hiding in plain sight. Nessa must choose: embrace her terrible potential, or watch everything she's fought for burn. Because at Confluence Academy, students leave as weapons... or they don't leave at all.