Rise Against: A Foundling novel (The Foundling Series)

Luce has come through hell, and now she's trying to pick up the pieces. Earth is getting ready for the war to end all wars: it's angels vs demons and Luce is the only one who seems worried about humanity, hapless pawns who are stuck in the middle of the battlefield. Between building an army and running for her life, she's got a lot on her plate.