The Book of Azrael

A desperate woman bound by an ancient debt and a reluctant god forced from exile collide in a battle that could shatter every world. Dianna has spent centuries serving a monster to save her sister, but when her master demands she hunt down the one person who terrifies her most—Samkiel, a powerful being she's tried hard to forget—she finds herself caught between her servitude and something far more dangerous: her heart. As mysterious forces threaten everything they hold dear, these sworn enemies must navigate a fragile alliance, electric tension, and the possibility that the only way to save the worlds might require them to trust each other completely.