King of Sword and Sky by C.L. Wilson — book slip

Rain Tairen Soul, the proud and haunted Fey King, returns to the mystical Fading Lands with his truemate, Ellysetta Baristani, to save the dying tairen and consummate their love. As they face an ancient evil threatening their world, Ellysetta must embrace her formidable powers and the magic bond she shares with Rain to protect their kingdom. Together, they must navigate political intrigues and forge an unbreakable bond of passion and power to save their people.

Third in the Tairen Soul series by C.L. Wilson.