Possession (Aris Duology, #1)

Mary was a regular girl before she became the host of a homicidal entity. Though powerless and nothing more than a voice in the back of her head, his presence changed everything for her. Now imprisoned and shunned, she’s learned to cohabitate and converses with Aris to stay sane. They read books, watch movies, and she listens to his plans for world domination. Maybe they've even become something like... friends? As the years pass, she's come to accept that this is all her life will ever be. Until, one day, the amulet keeping Aris inside of Mary begins to malfunction.

With the threat of his escape imminent, faced with the possibility of having a real life again, Mary starts to fight for freedom... forgetting all the while that Aris might have become a little too attached during their time together.

With cults, magic, and gods, Possession tells the story of a girl desperate for her own life, and a god, more interested in keeping her trapped in his own.