Kanata Shinozaki is the younger sister of Haruka Shinozaki, the male protagonist of the series. She is a first-year student at the same high school as her brother, placing her one grade level beneath him. Despite her small and youthful stature, she has a developed figure with an E-cup bust, a trait that consistently causes her brother's friend, Shizuku Ariyama, considerable mental distress whenever Kanata wears clothing that reveals her shape.

Her personality is dominated by a pronounced brother complex, and she is highly confident, perhaps overly so, in the depth of her brother's affection for her. This leads her to view Akiho Kosaka, her brother's girlfriend, as a romantic rival. In this rivalry, Kanata often behaves in a possessive and affectionately suggestive manner toward Haruka, attempting to appeal to him in ways she believes will challenge Akiho's position. However, her behavior is complicated by a profound contradiction: she possesses absolutely no practical knowledge or understanding of sexual matters. Her innocence on the subject means that while she frequently makes comments and gestures she believes are flirtatious, she is completely unaware of their actual innuendo-laden meanings. Her level of understanding in this area is described as being equivalent to that of an elementary school child. This combination of uninformed confidence and suggestiveness often puts her brother in awkward and embarrassing situations.

Visually and behaviorally, Kanata embodies distinctly feline characteristics. Her typical outfit includes a hoodie with cat ears attached and an artificial cat tail at the back. In a unique quirk, these accessories seem to move in sync with her emotions, and her overall mannerisms are notably cat-like. Her eyes are also depicted with vertical pupils, further reinforcing this visual theme. She is socially close with a female classmate named Misaki Aikawa, whom she has nicknamed "Sakiccho".