Rinka Kunitachi (国立 凜香/ Kunitachi Rinka) is a character of Kono Naka ni Hitori, Imouto ga Iru!.
During the series, Rinka is almost never seen outside of her Miryuin Academy uniform, with a blue ribbon on her hair and a braid on her left side.
Raised to be a lady since childhood, Rinka could come across as an uptight, haughty person. She is normally distant to others and has a tendency to be competitive. Rinka takes everything she does with a serious, no-nonsense altitude, which is shown in her setting up the Moral Committee to address what she saw as the "degrading moral" of the students.
However, deep underneath she is a friendly and loyal person (E.g willingly faking a call to save Shougo from the ploy of the school director.) In some occasions Rinka can be a childish person, unlike her everyday mature appearance.
Rinka first met with Shougo during the Miryuin Academy's ball, which she asked him to dance with her.
is the blonde first-year student council vice-president of Miryuin Private Academy and it is implied that she was brought up in a noble family. After Shogo transferred into Miryuin, Konoe calls her "a princess to the core." Rinka keeps Mana in line and is shown to be very good at dancing. . Rinka reveals that school director Genda asked her to find Shogo's sister so that he would have leverage when working with the Mikadono Group. Rinka uses Sagara's phone to make her fake sister announcement to threaten the director. Shogo was able to figure out her scheme and subsequently volunteered to pretend to be her lover to invalidate her engagement to director Genda's son. Thereafter, Rinka decided to pursue Shogo as her true boyfriend.