The Fall That Saved Us (Fallen 1)

Cassiel has given up the family tradition of demon hunting, leaving behind her sacred angelic duty and fated sword. What she can't leave behind are the scars. To cope, she spends her days immersed in work, pouring all her attention into New Haven Books, her small bookstore and anchor in the new world she's carved for herself.
But the past hasn't let go of Cassiel yet. When a succubus named Avitue arrives to claim her angel-touched soul, Cassiel's old hunter instincts flare, forcing her to choose between old knowledge and her truth. What should be a fatal seduction becomes a bargain neither woman expects. As they grow closer, Avitue is surprised to find her own pain reflected in Cassiel, a nephilim deemed fallen by her own family's standards.
By choosing trust, they reveal the lies that bind them. Falling for each other begins a path towards healing. But exorcising the effects of trauma is harder than naming it, and to explore the unfettered possibility Avitue represents, Cassiel must find a way to reclaim and redefine her angelic heritage.