The cold is in her bones
(Book)

Milla knows two things to be true: Demons are real, and fear will keep her safe. Milla's whole world is her family's farm. She is never allowed to travel to the village and her only friend is her beloved older brother, Niklas. When a bright-eyed girl named Iris comes to stay, Milla hopes her loneliness might finally be coming to an end. But Iris has a secret she's forbidden to share: The village is cursed by a demon who possesses girls at random, and the townspeople live in terror of who it will come for next. Now, it seems, the demon has come for Iris. When Iris is captured and imprisoned with other possessed girls, Milla leaves home to rescue her and break the curse forever. Her only company on the journey is a terrible new secret of her own: Milla is changing, too, and may soon be a demon herself. --from Amazon.