Rei is a petite girl from another world, a human who travels between different realms and the central world. Initially, Rei sacrifices a person to acquire the ability to traverse between worlds. To sustain this power, she must continue making such sacrifices. Rei loves torturing her victims before ending their pitiful lives, she finds joy in hearing their desperate voices. Rei has a regeneration ability, and she can control a string in her clothing to form something deadly to her advantage.