Chiaki is the youngest sister in elementary school. She is in class 5-2. Her high intelligence often makes her over-analyze simple situations; her speech patterns are those of an adult male and her wit is caustic. She is extremely cynical and tends to ignore idiotic behavior displayed by Kana and Makoto. She respects and adores Haruka, while often, if not always, resorts to beating Kana for her idiocy. Although 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 "bakayarÅ" (meaning 'dumbass' or simply 'you fool' in Japanese), which is a more forceful form for "idiot" in Japanese ("baka" being the less forceful term). Chiaki seems to know that Fujioka is genuinely in love with Kana. After talking with Haruka, Chiaki has come to associate Fujioka as a father figure and will often place herself on his lap when she seeks fatherly affection or to complete the family experience. "Chiaki" contains the kanji for "autumn".