Miki's twin sister. As children, Kozue and Miki were heralded as piano prodigies and held many concerts. When Miki fell ill, however, Kozue was forced to perform on her own, and it was revealed that she was only an average pianist who hid her deficiencies behind her brother's talent. Kozue was traumatized, and Miki's idyllic view of his sister was shattered. Kozue feels shadowed by her brother's talents and acts out by sleeping with different men.
