Black★Rock Shooter: Innocent Soul

Black★Rock Shooter ~Innocent Soul~ (Black★Rock Shooter -イノセントソウル-) is an action-fantasy manga series released in Kadokawa Shoten's Young Ace magazine. Sanami Suzuki (Net Ghost PoPiPa) is the author of the series.

The story follows a girl in the "Threshold" (狭間, Hazama), a world between Heaven and Earth. "Impure souls" — those that could not ascend to Heaven with the weight of their own burdens — have drifted to this world of constant warfare.

Characters

 * Rock - A girl with long black hair in twintails and a flame in her left eye. She wears a white striped shirt, thigh-high boots, and a black poncho. Her duty is to cleanse the souls of people who wander in the Threshold.
 * Ron - Rock's constant companion who comes in the form of a snake-like creature most of the time. When needed, it transforms into Rock's primary weapons: a hiltless katana and a cannon.
 * Dead - A girl with two black skeletal horns, wearing a sleeveless top. She wields a fancy three pronged sword and rather than releasing souls after she captures them, she eats them. She has two large black skulls as her companions.

Story
While searching for useful material Ret comes across Rock in an abandoned building and after witnessing her extreme hunger, he invites her to eat at his home. While leaving the building they encounter Io, Ret's younger sister and they then return home and Rock is shown around their home. Suddenly, Ret discovers Io has gone missing and sets out to find her with the help of Rock. Io sees Io's body and discovers she has been killed by "Jack the ripper" an Impure Soul that has murdered scores of people. Meanwhile, Rock hears a scream but is too late to save Ret, who has been fatally wounded by Jack. Rock enters combat with Jack the Ripper and defeats him with the use of Ron, who transforms into a large cannon. It is revealed that that Jack, after being sentence to death, has recreated the city of his murders in the Threshold. Ret in his dying breaths utters that even though they were just the product of the mind of a murderer, they still had fun playing with Rock.