Days of Blood and Starlight - Laini Taylor - paperback

Daughter of Smoke & Bone, book 2 of 3 completed series

Once upon a time, an angel and devil fell in love and dared to imagine a new way of living, one without massacres and torn throats and bonfires of the fallen, without revenants or bastard armies or children ripped from their mothers' arms to take their turn in the killing and dying.

Once, the lovers lay entwined in the moon's secret temple and dreamed of a world that was like a jewel-box without a jewel, a paradise waiting for them to find it and fill it with their happiness. 

This was not that world.