Devotion’s Covenant by Abigail Kelly

She’s got nothing to lose.
Petra Zaskodna knows the search for justice is a deadly game she’s bound to lose. As a covenless witch who manipulated her way into power, she’s used to living with a target on her back. Her position only grows more precarious with her mentor’s mysterious death. Desperate to uncover the truth, she’ll stoop to bargain with a man more dangerous than the enemies lurking in the dark: Shade.

He’s got everything to gain.
Silas Cuttcombe craves the taste of power. A demon with an unusual ability to wield magic, he’s spent decades spreading his reputation into every blighted corner of the continent and amassing incomprehensible wealth under the pseudonym Shade. He’s content with his life in the shadows, wreaking havoc when it suits him… until a pretty priestess comes begging for help and offering herself as payment. Exploiting their devil’s bargain at every opportunity, he finds a delicious sort of irony in bending the little golden goddess to his will.

Even gods fear what darkness devours.
It’s a sensual dance between predator and prey until the day danger catches up to Petra. Silas doesn’t care about the innocent lives hanging by a thread, nor the justice his witch seeks. She is his to play with, to protect, to break and put back together, piece by piece. Her enemies will learn there’s nothing more dangerous than a demon’s devotion — or his wrath.