Cloak of Night by Evelyn Skye

After the devastating Ceremony of Two Hundred Hearts, Sora, Daemon, Fairy, and Broomstick are truly alone in the fight to save their kingdom. Empress Aki is missing, and everyone else who could help them is a prisoner to the Dragon Prince’s mind control. At least Sora understands what they’re up against. Or so she believes, until she overhears the Dragon Prince bargaining with the god of war for immortality and learns that ryuu magic may be a more insidious danger than she realized. Suddenly, the stakes are higher and even more personal for Sora… Read more.