Demon Kissed (Ivy Taylor #1) by H.M. Ward & M. James

Description: The Valefar boy tricked Ivy Taylor into kissing him, but he took much more than a kiss - he stole her soul and left her within inches of death. By surviving, Ivy is drawn into the conflict between the Martis and the Valefar. The war between these two immortal forces has raged for millennia without distraction. Until now. 

Ivy is an anomaly-she is the only person who has ever walked away from a demon kiss alive. Her survival gives her unique and deadly abilities. Too powerful to ignore, Ivy is a threat to both armies. These two ancient enemies will stop at nothing to kill the seventeen-year-old. 

Surviving is nothing new for headstrong Ivy, but her survival has never depended on another person before. This time it does. And if she misplaces her trust, she's dead. To her horror, she starts falling in love at the worst possible time-with the enemy. He appears to be protecting her. But she can't be certain if he is trying to help her, or help himself to her power. For Ivy, trusting the right person is the difference between love and survival, or a deadly demon kiss. 

I really liked this book mostly because it isn't obvious like most mystery books. Its kinda suprising. And I like that!