The Promised Queen by Jeffe Kennedy

The fate of the world hangs in the balance as Con, Lia, and their allies sacrifice everything in a final bid to destroy the corrupt empire. Claim the hand that wears the ring, and the empire falls.

Conrí, former Crown Prince of Oriel, claimed the hand that wears the Abiding Ring, but the prophecy remains unfulfilled. Queen Euthalia of Calanthe returned to her island kingdom, but broken in mind and body. With the blood of war unleashing ancient terrors, Calanthe isn’t the haven it once was.

Lia must use her magical bond with Calanthe to save their people while Con fights to hold off the vengeful Emperor Anure and his wizards. Con and Lia will have to trust in each other—and in love—to fend off ultimate disaster.