What's Done In The Dark. The Underworld Duology, #1

Can an angel survive falling in love with the devil?Kane is the ruthless ruler of The Underworld, where power is absolute, and loyalty is demanded at the barrel of a gun. As judge, jury, and executioner, he controls every corner of the city's criminal empire-except for the part of him that longs for something more. The Playground, his brother's infamous brothel, offers a fleeting escape, but nothing truly holds his interest.
until her. Anaïs has always lived in the shadows, but her spirit remains unbroken. When she's forced into The Playground to repay her father's debts, she finds herself fighting to keep her innocence in a world determined to corrupt her. Her soft heart and quiet strength make her an unlikely survivor in a place designed to break the weak. Kane should dismiss her like the rest, but something about Anaïs stirs his long-dead heart.
She's a rare bloom in the filth of his world, and Kane will do whatever it takes to claim her for himself. But Anaïs isn't willing to be another pawn in his game-and taming her might cost him everything.