Between Blood And Darkness - Lili Mastronardi

All Adara Goodman wants is to survive senior year of high school without issues, but when a shadow with her appearance lands a student in the hospital after a fight, graduating and preparing for college are the least of her worries. The darkness that's followed her since childhood is resurfacing, and once its volatility causes the deaths of her loved ones, she's forced to seek help from the source of her curse-the Devil himself.

Desperate to restore life to those dearest to her, Adara agrees to a bargain: she must pass The Sixes, a series of trials created to grant Satanials, the soldiers of Hell, an opportunity to win back their souls. To qualify, she needs to be trained as one-not exactly a breeze judging by the rising tensions with her illusive mentor, the Daemon Prince Asmodeus, who seems determined to sabotage her.

Although Adara is fighting to complete her trials, they aren't her only battle. The longer she's surrounded by depravity and corruption, the more she struggles not to succumb to her own dark impulses. If she fails to complete The Sixes, not only does she lose her one chance to right her wrongs and defy her emerging monstrosity, but her soul will land in Praeteritus, the endless void separating the Nine Circles of Hell... until which time she'll return to the Circle of Treachery to serve as the Devil's Satanial for eternity.