He Who Holds My Soul by Shannon V. Velzen — book slip

Daisy Sandoval's life takes a dark turn when her soul is sold to Korithax, the Prince of Hell, by the very person meant to protect her. Korithax, bound by ancient laws, needs a queen to claim his shattered throne.

As Daisy is thrust into a world of gods, monsters, and burning kingdoms, she must navigate court politics and celestial enemies. An unexpected connection forms between Daisy and Korithax, but love was never part of the deal.

With ancient powers awakening within her, Daisy faces a choice: embrace the darkness or wield it to challenge the heavens.

First in 'The Fire and Silence Trilogy'.