Notorious Nix - Nix Trilogy, #2

Demonic possession...from the demon's point of view. Dark horror for the twisted mind.  Nix has seen a lot of stupid humans do a lot of stupid things, but nothing like this. A pleasant night at the carnival takes a weird turn when Nix finds herself abducted by old foes. The paranormal hunters need her help and somehow think that kidnapping-with a side of extortion-is the way to persuade her to cooperate. One step away from death, the hunters are on the run from their own kind, stalked by vengeful demons, and in way over their heads.
Nix is a demon with a love for violence, mayhem, and darkness, so she can't imagine why they want to make a deal with her. But if it's darkness they want, Nix always delivers.  Note: This book contains graphic violence. Reader discretion advised.