Reina Kousaka is a teenage girl with a slender build and a relatively short stature. Described as beautiful in the light novels, she has a fair complexion that complements her striking features. Her long, straight black hair reaches down to her lower back, often styled in a ponytail, though she occasionally leaves two longer strands to drape over her shoulders and two shorter strands framing her face. Her violet eyes further enhance her distinctive appearance.

Reina is typically seen wearing the standard Kitauji High School uniform for first-year female students, maintaining a neat and composed appearance.

Reina Kousaka is a calm, quiet, and individualistic girl with a deep passion for music. While she maintains a polite demeanor, especially toward her seniors, she is often perceived as aloof due to her tendency to wear a serious expression. Her somewhat cold and occasionally blunt nature comes to the forefront when someone speaks ill of Noboru Taki, the teacher she harbors a crush on, which sometimes leads to gossip about her.

Portrayed as a mysterious character, Reina doesn’t easily open up to others and tends to distance herself from people who don’t capture her interest. Her pride as a musician can make her appear standoffish, and she is unafraid to speak bluntly about her craft, often leading to difficulty in making friends. Focused intensely on her drive for musical success, she seems emotionally distant, yet her passion remains the core of her identity.

However, as Reina grows closer to Kumiko Oumae, a more vulnerable and supportive side of her begins to emerge. Through their budding friendship, Reina gradually lowers her emotional guard. She confides in Kumiko about her desire to become something truly special—an aspiration that fuels her dedication to the trumpet. Reina deeply treasures her trumpet, a gift from her parents during her junior high school years, and views it as an integral part of her journey toward self-discovery.

Over the course of the series, Reina evolves emotionally. She begins to show more empathy, even apologizing for her previous rude behavior—a first on screen. Kumiko later remarks on how Reina has changed, noting her newfound openness and willingness to interact with others, including classmates like Hazuki Katou and Midori.

Reina Kousaka has been playing the trumpet from a very young age, and her love for music continues to drive her at Kitauji High School.

She and Kumiko Oumae attended the same middle school, where they were both members of the junior high school concert band. During their time in middle school, Kumiko witnessed a moment where Reina was crying after the band fell just short of advancing to the next round. Kumiko, initially assuming that Reina’s tears were from joy, later realized that Reina was actually devastated. She had just lost her final opportunity to compete in the nationals as a middle school student. When Kumiko asked if they could still make it to the Nationals, Reina, unable to hold back her emotions, ran away sobbing, leaving Kumiko feeling guilty and speechless.

Additionally, it is revealed that Noboru Taki and Reina’s families have known each other for years, with Taki-sensei having known Reina since she was a child, even before the events of the series.

On her first day at Kitauji High School, Reina Kousaka decided to join the band and continue playing the trumpet, much to the delight ofAsuka Tanaka, who warmly welcomed her into the group.

However, Kumiko Oumae, along with Hazuki Katou and Sapphire Kawashima, overheard Reina’s admission and was shocked to see her again, especially given the emotional history between them from their junior high school days.

Throughout the series, Kumiko feels increasingly awkward around Reina, still affected by their past encounter. In contrast, Reina does not display the same discomfort, maintaining a more composed attitude. Over time, however, their relationship evolves, and Reina gradually grows closer to Kumiko. Their bond deepens into a friendship, and with Kumiko’s support, Reina’s motivation to improve as a trumpet player intensifies.

Kitauji High School Concert Band

Kumiko Oumae
In a flashback to their middle school years, the first episode shows Kumiko noticing Reina crying after their band’s ranking was revealed—a high placement that was still insufficient for advancing to the next round. Kumiko initially assumed Reina’s tears were those of joy. However, Reina was actually devastated, having lost her final chance to make it to the nationals as a middle school student. She ran away sobbing, leaving Kumiko feeling speechless and guilty.

As a result of this incident, the two enter high school with an uncertain relationship. Kumiko tries several times to confront Reina about what happened but struggles with her own awkwardness, while Reina reacts with her usual composure. Over time, however, the two begin to grow closer through tentative conversations, gradually developing a deep bond. Their growing connection is often marked by mutual blushing and occasional embarrassment in each other’s presence.

In episode 8, Kumiko accidentally invites Reina to attend the Agata Festival with her. Despite their wariness toward each other, both girls reluctantly follow through with the invitation. As they talk more, they eventually begin calling each other by their first names, signaling the restoration of their friendship.

With their bond stronger than ever, Kumiko becomes Reina’s closest friend. The two share a deep trust and support for one another, including a heartfelt “confession of love” from Kumiko, who promises to always stand by Reina—even if it means competing against Kaori. She declares, “I wouldn’t abandon you, even if it costs my life.”

Kaori Nakaseko
Kaori is Reina’s senior in the trumpet section. Their relationship is friendly and respectful, with a healthy rivalry based on their shared passion for music. Although Reina is younger, she returns Kaori’s respect, and the two maintain a positive and professional relationship within the band.

Yuuko Yoshikawa
Yuuko, a second-year trumpet player, feels strong jealousy toward Reina. This stems not only from Reina’s superior skills in the trumpet section but also from Yuuko’s obsession with Kaori, whom Reina is close to. Yuuko often expresses annoyance when Reina plays outside of rehearsals, yet Reina continues to treat her with respect, mindful of her position as an underclassman.

Teachers

Noboru Taki
Throughout the early episodes, subtle hints suggest that Reina has romantic feelings for Taki, especially evident when she reacts with frustration after Shuuichi mentions Taki-sensei’s disapproval. This is later confirmed when Reina admits to Kumiko that she has a crush on Taki.

In the light novels, it’s revealed that Reina has a daily ritual of visiting Taki’s office first thing in the morning, before practicing the trumpet and heading to her first class. She even finds excuses to visit him during the day, no matter how trivial. Additionally, Taki’s family and Reina’s family have known each other for years. Taki’s father, Tooru Taki, and Reina’s father taught together at Kitauji, and Taki’s sister is a longtime acquaintance of Reina’s. Taki himself has known Reina since she was a child, often comforting her with music.

In the light novels, Reina’s jealousy flares when she suspects Taki has a girlfriend (later revealed to be false). In a fit of rage, she smashes a glass and performs her solo with noticeably less emotion and sensitivity, causing concern for Taki as the competition approaches. However, this emotional outburst does not occur in the anime.

At the end of the third novel, Reina confesses her love to Taki after the final concert. However, because of the circumstances, Taki interprets her words as a gesture of respect rather than a romantic confession. Despite knowing her feelings were misunderstood, Reina smiles, content with his polite response. Later, she learns from Taki that his wife had passed away, further deepening the complexity of their relationship.