Koto Nakazawa is a swordswoman renowned for her twin-blade technique. She exhibits distinctive features including brown hair styled in a ponytail reaching her chest and vivid green eyes. Her attire consists of traditional hakama, and she carries a katana. Nakazawa demonstrates her combat prowess in the Gekkenkai, a fencing tournament where competitors battle with wooden swords. She ranks among the final eight contestants, standing alongside notable fighters such as Shizuma Origasa and Kyōshirō Shuragami. Her twin-sword style becomes pivotal when swordsman Tachibana Youjirou is murdered before the tournament; the fatal wounds suggest the killer used twin blades, implicating Nakazawa or another with matching skills. She bears psychological and physical scars from past traumas, reflecting a character laden with profound emotional burdens.