Miki Murakoshi is a high school student at Ouka High School and one of the main characters in the series. She is a sixteen-year-old girl with brown hair and ochre-coloured eyes. She serves as the closest friend and primary social counterpart of the protagonist, Mayu Morita. In contrast to Mayu’s extreme reticence, Miki is exceptionally talkative, energetic, and outgoing. She naturally dominates conversations and is often described as a genki girl, meaning she has a cheerful and lively disposition. She is also very interested in boys, and this interest occasionally drives her actions and remarks. Her personality is marked by warmth, sincerity, and empathy; she is genuinely caring toward her friends and prioritises their needs. Miki is part of a four-girl ensemble that also includes Mayu, Hana Matsuzaka, and Chihiro. Her role in the story is to provide a lively counterbalance to Mayu’s silence, often speaking for the group or keeping social interactions moving. Her talkative nature sometimes creates humorous situations, especially when Mayu’s long pauses are juxtaposed with Miki’s rapid chatter. While she does not undergo a dramatic character arc, Miki’s presence highlights the quiet strength of her friendships and the comfortable dynamic within the circle of classmates. She has no special abilities, but her gregariousness and genuine kindness are her defining traits.