Jack's lover.
Reiye carries a sharp Bowie knife stained with the blood of the men she has put to their graves. In her pocket is a pouch in which she keeps pieces of cloth from the clothes of them men she killed. She has about a hundred of these.
After seeing her own family butchered, she went after the perpetrators instead of going to the cops for help. She knew the cops were corrupt and only catered to the rich, and her family was lower-middle-class. After getting that thrill of the blood on her hands, she became a wanton murderer. Not only did she get a rush from each slaying, but she got a slight sexual thrill as well. Attracted by men who killed people, she was attracted to Jack.