Jun Gotō, who is affectionately known by the nickname Jun-tan, is one of the three central characters in her story. She is a fifth-grade elementary school student with a gentle and tender-hearted nature that is immediately noticeable to those around her. Physically, Jun-tan is characterized by her long, light purple straight hair, which she often wears with a side ponytail, and her matching light purple eyes. Her image color is purple, reflecting her calm and soft presence.

Jun-tan lives with her two closest friends, Nozomi Momijidani and Sora Kaneshiro, at a children's welfare center called Little Wing, having been raised alongside them like sisters since early childhood. Of the three, Jun-tan is known as the crybaby of the group, possessing a very shy, timid, and sensitive personality that often leads her to tears. She has a habit of saying a particular verbal tic, which adds to her endearing and innocent demeanor. Despite her timidity, she demonstrates considerable inner strength and assertiveness when it truly matters, hesitating at first but always finding the courage to speak her mind.

The primary motivation for Jun-tan and her friends is their shared dream to bring people together through music. They seek to hold a concert as a way to create lasting memories and express their gratitude. Jun-tan plays a vital role within their band, Lien de Famille, serving as the main vocalist and lead guitarist. Her musical talent is exceptional, particularly her extraordinary auditory ability, which amounts to a form of perfect pitch. This skill allows her to recognize that the reclusive high school student Kyō Nukui was the anonymous composer behind songs she admired online, a discovery that initiates the central plot. Her musical prowess does not stop at performance; she also grows into a capable composer, writing original music for the band.

Jun-tan's relationship with Kyō is a key part of her development. She initially mistakes him for an older, professional music producer due to the formal language in her emails, but she quickly comes to see him as a close, reliable older brother figure. Despite her shyness, she tries very hard to befriend him and often acts as a source of emotional healing and comfort for Kyō, contrasting with his own anxious and withdrawn personality. Over the course of the story, while she remains fundamentally shy, Jun-tan demonstrates a clear developmental arc. She transitions from a purely timid follower into a more confident and assertive young musician, stepping up as an effective leader whose pure-hearted yet determined personality drives the band forward and inspires those around her.