Before Chise became an ultimate weapon, maimed Captain Mizuki was a dedicated soldier who sought only to return to the battlefield to defend her country, so she volunteered for an experimental program which turned her into a cyborg weapon. When it became clear that Mizuki had reached the limited of her development, though, ordinary high school senior Chise was drafted and transformed into something even greater, though also far more psychologically fragile. Because Mizuki's nature allows her to hear Chise's thoughts, she knows what the commanders do not: the true toll that being a weapon has on Chise. (Source: ANN)