Kodachi, known as "The Black Rose" in the gymnastics world, is introduced as Tatewaki Kuno's sister and a student at St. Hebereke School for Girls (St. Bacchus School for Girls in the manga). Unlike many other characters who attend Furinkan's co-ed school, Kodachi specializes in "Martial Arts Rhythmic Gymnastics" and leads her school's team. She frequently initiates attacks on her opponents using various weapons like swords or a giant mallet to incapacitate them, thereby winning by default. She refers to this tactic as "fighting fairly before the match." Prior to encountering Ranma, she had rarely, if ever, lost a competition due to these aggressive strategies. When her direct methods failed, she resorted to more underhanded tactics, such as attempting to shake hands with hidden thumbtacks. She also enjoys using paralysis gas and sleeping powders on people, even without clear motives.
Kodachi becomes infatuated with male Ranma after he rescues her from falling off the roof of the Tendo Dojo, playing the role of her 'knight in shining armor.' Thus, she is the only one among his admirers without any formal or informal claim to him. Despite this, she considers him her lover and is determined to make him hers by any means necessary. Her perspective contrasts with that of her brother; while Tatewaki despises Ranma's male form because of his engagement to Akane and his supposed enslavement of the mysterious 'pigtailed girl,' Kodachi dislikes Ranma's female form, whom she views as a romantic rival. Despite his general dislike for Ranma, Tatewaki has enthusiastically endorsed their relationship, hoping it would free Akane for himself. Secretly, he imagines they would have a miserable life together.
