Winds of Twilight: The Last Prince of Illumis:

In a world split between endless day and eternal night, two realms teeter on the edge of war. At the heart of it stands Prince Aelion of Illumis, a kingdom where the sun never sets, and peace hangs by a thread. When a rare alliance brings him face to face with a figure from the shadowed lands of Noctyra, long-held truths begin to fracture. Caught between duty and desire, history and the unknown, Aelion must confront more than politics. He must face the weight of his own legacy. Winds of Twi...