Io

Io (イオ, Io) is a minor character in Black★Rock Shooter: Innocent Soul.

History
Io and her older brother Leto were two of the eighty-six victims murdered by serial killer Jack in their former lives. Jack's thirst for murder remains even after execution, and he lingers in the Threshold as a Stagnant Soul, where he creates an illusive town and traps the souls of his murder victims so he can repeatedly murder them for pleasure.

Not remembering that they were already been murdered in the past, Leto and Io live their daily lives in Jack's town, but wary of the ongoing serial murders, which takes place every full moon. One day, Io goes out to find Leto, who encounters Rock while searching for scraps in a dilapidated building, as he is late for home. Leto invite Rock over for dinner and shows her his workshop, where he crafts jewelry out of scraps. Io is delighted to have Rock's presence at home, because all of her friends have already left town according to Leto.

At night, Io ventures out at night under the full moon to craft a floral wreath for Rock, believing the the talisman that Leto made for her will protect her. However, by the time Leto notices that Io is missing and finds her on the street, Jack has already claimed her as his fifty-fourth victim. Shocked by the discovery as well as Jack's appearance, Leto is paralyzed by fear and fatally wounded before Rock arrives at the scene, who then reveals her identity as a Black Star and destroys Jack.

Rock's partner, Ron, tells Leto that he and his sister are two of the many souls trapped by Jack in the Threshold. As the illusions created by Jack begin to fade, Leto is saddened by the revelation, but Io in her last moment holds Leto's hand, saying that she is nonetheless happy to be with Leto again and getting to meet Rock in the Threshold. Leto agrees, and the two siblings embrace each other before dissipating, leaving Rock behind who is slightly wavered by their final words.