Minami has short and spikey black hair with one prominent spike highlighted in light green on colored pages. She is one of the shortest Shiunji siblings, second only to Seiha Shiunji. She often pairs her school uniform with a lime green sweater tied across her shoulders. She is the only sibling who does not wear socks that extend visibly past her school shoes. Like her twin brother, she has a more androgynous appearance. Unlike her sisters, she is more frequently seen in athletic wear, shorts, or casual clothing, and Arata was noticeably surprised the first time he saw her wearing a skirt.

Minami is very cheerful and spritely, and is arguably the most athletically gifted of the Shiunji siblings. She is considered a child prodigy in tennis and has been scouted multiple times by professionals since she began entering and winning several middle school tennis competitions. Many believe she will eventually compete in the Olympics. Despite her exceptional athletic ability, she is the only Shiunji sibling who struggles significantly with academics, even having difficulty with basic addition. Unlike her sisters, many of Minami’s fans in the Shiunji fan club are girls.

Arata has described her as the funnest Shiunji sibling to be around, and she is often seen wearing a bright smile. While naturally positive, she has a habit of hiding her emotions when something bad happens, trying to maintain an outwardly cheerful demeanor so her feelings will not affect the people around her.

Shion Shiunji grew up as one of the youngest members of the Shiunji family, living a comfortable life alongside his siblings in their wealthy household. Although he was always seen as the most easygoing among them, he quietly developed a sense of independence and curiosity that set him apart. While his siblings focused on academics, social responsibilities, or personal goals, Shion often preferred to stay in his own world, spending most of his time playing games or relaxing.

His life changed after their father revealed that none of the Shiunji siblings were related by blood. Unlike some of the others who struggled with the emotional implications, Shion directed his energy toward uncovering the truth of his own origins. He learned that he was born in Karuizawa, which motivated him to search the town for clues about his birth parents. Despite his efforts, he found no clear information, but the experience strengthened his understanding of who he is beyond the family name.

Even with this unresolved chapter in his life, Shion maintains his calm and unbothered demeanor. His relationship with his girlfriend Yuu and his interactions with Arata and the rest of the siblings highlight his loyalty and perceptiveness, showing that beneath his laid back nature, he carries a quiet desire to understand where he truly came from.