Manor Saffron by A.J. Flowers

Every kingdom has an origin… this is Manor Saffron’s founding story. There are four great Manors across Terra that care for the angels cast from Celestia, but it had not always been that way.
Valeria is the first wingless angel to survive in a world overrun by demons and malice. Raised on the unforgiving Obsidian Sea, she’ll learn what it means to be Windborn, and what she’ll have to sacrifice to change a broken world she’s grown to love.
The humans huddle in the last remaining stronghold: Leocivat. They are ruled by a governing force of Hallowed known as the Coterie. Nile, their youngest and newest addition, strives to understand how the demons have come to dominate the outlands and continue to ravage the world. He will find out what it takes stop them, even if he’s the only one willing to try.
Nile needs an angel. Valeria needs a guide. When Valeria and Nile join forces, the foundation of the world will be shaken, and a new one will rise.