Vivian from Paranormalcy is the myserious killer that is able to suck the soul from other parnormals. When seh does thi sshe leaves them dead. She was created by the faeries like Evie was and is related to her somewhat through that. She rationalizes what she does by saying she is releasing them from their life trapped on earth. What is really happening is that they are being trapped in her body. It is only at the end when Evie kills her that the souls are all released.