Kazuki is Yuuji's elder sister as well as the one who taught him throughout the earlier periods of his life. Contrary to the norm, Kazuki was the center pillar of the family instead of her father. She was the one earning all the living expenses and no one could go against her.
Despite her delicate and diminutive body, she has brilliant intellect and excels in quick-witted judgement to the point that she has been labelled as a genius. She is the same age as Amane, both of which attended the same school "Takizono Private" and was also an active member of the basketball team for the aforementioned academy.
