A Light in the Shadows - Avery H. Queen

Isabella Starr is sixteen and the only person in her village who isn't a Scaras. Everyone is a Scaras, soldiers trained to kill demons. Except Isabella, who spends most days with her nose in a book. And because of this, she discovers something extraordinary. But after an unforgettable incident, Isabella finds herself face to face with the Demon Prince, the leader of the demons.

Then Isabelle isn't sure what to believe anymore. Aaron, the Demon Prince, he saved her life. And as days turn into weeks, Isabella sees a side of Aaron that she didn't know existed. There's a part of him that's kind and honest. And Isabella can't help but get close to him.

But then, Aaron's mother, the Queen of Death, starts to lead an army of demons to Isabella's village. Aaron and Isabella get ready to race there to stop a war. Will their love for each other bring peace to their world, or will it make the war rage on until everyone is dead?