A War of Mortal Gods. Mortal Gods, #1

Two gods became mortal to find true love. Fate made them enemy commanders in a holy war. Mara Soreth commands the armies of Istrava, a nation that kneels to no god. Aren Valis is High Marshal of Caldris, an empire built on vows, bells, and sacred obedience. They meet as enemies across a battlefield soaked in blood, each certain the other is the monster their people were taught to fear. Then the prayers begin going wrong.
Caldrin vows reach Mara. Istravan pleas for mercy reach Aren. Every battle draws them closer to a truth neither nation can survive: the gods their peoples worship may be hidden in enemy flesh. As Mara and Aren are forced beneath ruined altars, across forbidden thresholds, and into a love neither command nor mercy can excuse, the war around them becomes something worse than political. It becomes theological.
If they are gods, every life they have taken may have belonged to their own worshippers. If they are only mortal, then heaven is lying. And if love requires the freedom to refuse, worship may be the most dangerous form of devotion. A War of Mortal Gods is the first book in The Mortal Gods trilogy, a dark epic romantic fantasy of enemy commanders, holy war, hidden divinity, battlefield mercy, and love that refuses to become worship.