Miyabi Kannagi (神凪 雅/Kannagi Miyabi) is one of the heroines of the Kono Naka ni Hitori, Imouto ga Iru! series.
Miyabi is a petite girl for her age, which sometime could be mistaken as a junior high student.
Miyabi childish look is evenly matched by her childish personality. She is lousy, energetic, and can quickly change her mood. Around Shougo, these characteristics are amplified, and Miyabi acts like his clingy little sister.
However, Miyabi was not always this way. As Konoe revealed to Shougo, on her first year at the Miryuin Academy, Miyabi secluded herself from her class and almost never interact with anyone else.
Like Konoe, Miyabi is very possessive of Shougo and will become jealous if she perceive any potential rival for his affection. However, ultimately she is concern about his happiness and will do anything, even ignoring her feeling, if Shougo is happy.
Another classmate of Shogo and a member of the swimming club. Miyabi revealed that she met Shogo at the hospital where he was recovering from his accident—whenever her father went in for treatments, she would play outside with him. When Shogo first attempted to speak to her upon meeting her in class, she refused to talk to him. After that, she overheard his conversation with Konoe and after seeing them almost kiss, demands that he kiss her. She reasons that after Shogo calls Konoe "just a classmate," it should be fine for him to kiss her as well. When she tells Shogo of their previous relationship together, she also confesses (with Konoe present) that she fell in love with Shogo as a child and along with Konoe was elated upon learning of his transfer to their school. She is competitive with Konoe about wanting to marry Shogo, to the point where they will argue about it in front of him. As the story progresses, she often interrupts romantic moments between Shogo and Konoe. At the end of the anime and in volume 4 of the novel, she is believed to be his sister. However, in volume 8, after another DNA test it is discovered that she is actually his cousin. Eventually, Miyabi becomes Shogo's stepsister when her father and Kanoko marry.