Kana is the middle sister of the Minami household and is in her second year of junior-high school. She is fairly ill-mannered and lazy compared to her sisters, preferring to spend her spare time lounging around the house and doing as little work as possible. However, depending on her overall mood and boredom levels, she is unarguably the most hyperactive of the bunch. She can be quite selfish at times, and will frequently play pranks on or tease her younger sister, Chiaki. She has a strong craving for food, especially chocolate and sweets, but is a terrible cook, so she often relies on Haruka or even Chiaki to do the cooking for her.

Haruka is the oldest sister and in her second year of high school. She has been taking care of her younger sisters for many years, and this fact has led to some misunderstandings with her classmates. Haruka is the most reliable of the three sisters, but becomes infinitely lazy when she is by herself. She was called Banchō (gang leader) during her junior-high days, though it is revealed soon after that it was simply a title. She is the only person whom Chiaki dares not oppose or be rude to; Chiaki views her as a role model and greatly respects her. This can be seen in her tendency to address Haruka as "nee-sama" instead of the more usual and casual "nee-san"; and the only person Chiaki uses polite Japanese with (even though it is not customary for siblings to use polite Japanese towards each other). "Haruka" contains the kanji for "spring".

Chiaki is the youngest sister in elementary school. She is in class 5-2 (a reference to Kyo no Gononi). Her apparent high intelligence often makes her overanalyse simple stuff. She also tends to ignore idiotic behaviour displayed by Kana and Makoto. Even being the youngest, she is the meanest out of the three; most of the time, she is quiet during group activities, and almost always uses the word "bakayarō", which is a more forceful form for "idiot" in Japanese ("baka" being the less forceful term).