Kirin Morino is a central character who serves as a catalyst for the emotional core of her story. She is a girl of middle school age, the same as her second cousin, Ryo Machiko. Despite being the same age, Kirin has a notably short stature that makes her appear much younger, around twelve years old. She lives in a rural area and commutes to Tokyo on weekends to attend an art cram school, with the goal of eventually being accepted into an art-focused high school. Because her home is far from the city, she stays at her cousin Ryo's apartment every Saturday night before her Sunday classes.

In terms of personality, Kirin is initially characterized as shy and somewhat childish, though she is also extremely polite and well-mannered. She can be quite expressive, especially when it comes to food, reacting dynamically and with great enthusiasm to the meals she is served. This exuberance can sometimes manifest as jealousy, as seen when she becomes envious of Ryo's school friends who have tasted her cooking. Her behavior sometimes gives her a "country bumpkin" quality as she experiences the offerings of Tokyo for the first time. Kirin is also a voracious eater with a big appetite, which contrasts with her small physical frame.

Kirin's primary role in the story is tied to her relationship with Ryo. At the beginning of the narrative, Ryo has been living alone since her grandmother passed away and has lost the ability to enjoy her own cooking. When Kirin begins staying over and sharing meals with her, Ryo rediscovers that food tastes good when eaten together with someone else. Beyond this initial function as a dining companion, Kirin's role evolves. A key moment in her development occurs when their friend Shiina points out that Kirin simply enjoys Ryo's cooking without contributing any effort, accusing her of "freeloading". Kirin takes this criticism to heart and, despite having no real cooking experience, decides to take on the challenge of preparing a meal for Ryo. Her initial attempts are not without mishap, as she proves to be clumsy in the kitchen, but her sincere effort is ultimately successful. This event marks a turning point where Kirin moves from being solely a receiver of care to also being a giver, trying to cook for Ryo more often. This creates a more balanced dynamic in their relationship, as Ryo, who is naturally a caretaker, learns to accept being cared for in return.

Despite her lack of culinary finesse, Kirin possesses other notable abilities that set her apart. She has unrivaled athletic ability among the characters in the series and is described as a powerful child, which contrasts humorously with her small stature. She is also a big eater, capable of consuming large portions. Conversely, she is bad at general housework and has been known to break dishes when trying to help in the kitchen. She also has a childish dislike for certain foods, specifically carrots.

Kirin's key relationships outside of Ryo include her friendship with Shiina, who is a mutual friend from the art cram school and a source of honest feedback. Her family life is also touched upon. She has a strict and temperamental mother who often argues with her, and a calm, loving, and somewhat eccentric father. By the end of the television series, Kirin's development culminates in her moving into Ryo's apartment to live with her full-time, and she later attends the same high school as Ryo and Shiina. In high school, she joins the basketball club, further utilizing her athletic talents, and her friends and teammates affectionately nickname her "Kii".