House of Dusk by Deva Fagan

A romantic epic fantasy featuring a fire-wielding nun grappling with her dark past and a young spy caught between her mission and a growing attraction to an enemy princess

With complex relationships, a rich and mythic world, and brisk pacing, this standalone novel is perfect for fans of Tasha Suri, Samantha Shannon, and Shannon Chakraborty
Ten years ago, Sephre left behind her life as a war hero and took holy vows to seek redemption for her crimes, wielding the flames of the Phoenix to purify the dead. But as corpses rise, a long-dead god stirs, and shadowy serpents creep from the underworld, she has no choice but to draw on the very past she’s been trying so hard to forget.
Orphaned by the same war Sephre helped win, Yeneris has trained half her life to be the perfect spy, a blade slipped deep into the palace of her enemies. Undercover as bodyguard to Sinoe, a princess whose tears unleash prophecy, Yeneris is searching for the stolen bones of a saint. Her growing attraction to the princess, however, is proving dangerous, and Yeneris struggles to balance her feelings for Sinoe with her duty to her people.