The Book of One in Bloomington, MN

Angels and Demons don't mix. That's what everyone believes, at least.
In 10th Century Rome, angels and demons swarm over the city, seeking to corrupt - or defend - the church.
Kalili is a demon. Her life is her mission - and she's bored. After six millennia of corrupting humans, she's been there and done that. This assignment is no different, until her imp informs her there's an angel assigned to eliminate her.
Faith is that angel. At once ancient and innocent, she's in over her head on this assignment. She's an angel, though, charged with a mission, so she confronts the demon, and...
Neither of them could have planned what happened next.
Now they're both searching for answers to questions they didn't know needed asking.
And the answers they get will change everything they thought they knew.