Lost Bastard:

Deva Landry is relieved to be rescued from the MC princess life. But now the angel who saved her is back to collect payment. The cost? Deva is assigned to babysit bad-boy cage fighter Aleksei Voronov, forcing her back into the murky underworld of Chicago. Prepared for the worst, she’s shocked to uncover a kindred spirit, a wounded soul like hers. Chaos strikes and the two are thrown together on an impromptu mission to stop a city-wide massacre. Deva’s always prepared for battle, but can she overcome the burning desire for the inked deviant who represents everything she thought she left behind?