Ella George and the Demons.

The demons. They ruled the world for thousands of years, until one day, they just left. Out of the blue. So a new society had to be formed, with Hunters. Demons still came out of course, but they could be defeated and weren't as big of a problem. But the demons were planning a comeback. They couldn't be permanently destroyed. At least that's what they thought, until Ella George came along.

Ella George is your average everything. Think of a stereotypical nerd and that's her. She's a social outcast and doesn't have any friends. Ella's 15 and no one thinks everything of her. But one day, someone starts following her.