The West Wind by Alexandria Warwick

Long before civilization, there were the gods. And before the gods, there was the earth, the celestial bodies, and air given flesh. They are the Anemoi—the Four Winds—and they have been banished to the four corners of the world.
Brielle of Thornbrook has dedicated her life to the abbey. She spends her days forging iron and studying the Text, all in preparation of becoming an acolyte—a shepherd of the Father. Twenty-one years on this earth and she has never touched a man. And she never will.
Yet dark things uncoil beyond Thornbrook’s high stone walls. A chance encounter with an alluring stranger leads Brielle to Under, where the air breathes rot and the roots grow black. Zephyrus, Bringer of Spring, with eyes of green.
In Under, those Brielle can trust are few, least of all Zephyrus. But never has a man so thoroughly ensnared her. When faith and heart collide, Brielle learns how quickly threads unravel, even her most sacred vow: thou shalt not forsake the Father. For He is the Kingdom, and the Power, and the Glory. Forever and ever. Amen.