Some girl was being hunted, died and burned, but was possessed. I guess she is the main demon for whole movie, which was dumb to have someone be the "evil".
Suicidal girl has a problem, Mia's boyfriend wanted to help, so gave her necklace. She starts going mad, and steals the car and crashes it in water, sees some crazy demon girl, like one who is burned. She spits out black vines who rape her, by going into her, and imagine she is now totally fucked.
Glasses opened book, and released it. She killed his dog with a hammer, and he found the bridge broken. She burned herself in the shower.
Shes now super possessed and throws up red shit…