Frostblood

Seventeen-year-old Ruby is a fireblood who must hide her powers of heat and flame from the cruel frostblood ruling class that wants to destroy all that are left of her kind. So when her mother is killed for protecting her and rebel frostbloods demand her help to kill their rampaging king, she agrees. But Ruby's powers are unpredictable, and she's not sure she's willing to let the rebels and an infuriating (yet irresistible) young man called Arcus use her as their weapon. All she wants is revenge, but before they can take action, Ruby is captured and forced to fight for her life in tournaments that pit fireblood prisoners against frostblood champions.