Movie
Description
Kōji Mihama, a human male born January 14th in Tokyo with blood type O, possesses striking chartreuse eyes and ash-brown shoulder-length hair, later often tied in a small ponytail. Standing tall at 185cm, he wears his deceased father Takeyuki Mihama's dog tag and a purple Over The Rainbow wristband matching his unit. A Capricorn, he grew up in a well-off Tokyo household where his mother Natsuko worked and his father acted as househusband. Takeyuki taught Kōji cooking, baking, and guitar, fostering a bright childhood filled with musical bonding and friendship with Kazuki Nishina.

Takeyuki's death dramatically shifted Kōji's personality to quiet and gloomy, rarely smiling. Despite Natsuko's opposition to songwriting, he enrolled at Edel Rose Academy at thirteen. Peers mocked his "childish" music until Hiro Hayami, impressed by his talent, befriended him. This sparked a close partnership; Kōji agreed to write songs for their joint idol debut. Two years later, in their third year of middle school, Kōji composed "Pride" for their unit debut. On supervisor Jin Norizuki's advice, citing publicity, Hiro claimed sole credit. Feeling betrayed, Kōji confronted Hiro and quit both the unit and Edel Rose, sinking into depression.

His creative slump ended upon meeting Naru Ayase, whose earnest request for a song inspired him to compose again. Later encountering Ito Suzuno, she criticized his music as "half-hearted." When Hiro asked Ito to compose for him, Kōji intervened, fearing she would suffer the same theft he experienced. To protect her, he gave "Pride" to Hiro, preventing Ito from submitting her own work. Romantic feelings blossomed between Kōji and Ito, leading to a confession and kiss in a park. Their relationship faced opposition due to a historical conflict between the Mihama and Suzuno families. Both families forbade their union, prompting Ito to briefly break up. Kōji confronted Natsuko about moving past the feud, while Ito reconciled with help from Otoha Takanashi. The families eventually made peace, allowing them to resume dating.

Kōji reconciled with Hiro after Kazuki facilitated communication. During a rematch between Kazuki and Hiro, Kōji composed "Freedom," embedding lyrics mirroring Hiro's middle-school idealism to convey lingering care. After Hiro apologized for the plagiarism and planned to quit performing, Kazuki and Kōji persuaded him to return. The trio formed Over The Rainbow, symbolizing their renewed bond. Kōji designed the unit's costumes and served as its youngest member.

He later accepted an offer to compose a Hollywood film soundtrack in America, aiding Edel Rose's debt repayment. His career expanded to hosting a TV cooking show and composing extensively, creating songs like "Reboot," "Athletic Core," and collaborations such as "Pouring Rain HAPPY" with Ito. He joined the band "Cross Road" with Ito and her brother, Yu Suzuno. His compositions, noted for their "demonic" charm, attracted international offers, maintaining his busy schedule.

Typically kind and soft-spoken yet easily angered, Kōji is described as strict but caring, especially toward loved ones. He exhibits mysterious or unpredictable traits but acts with good intentions. His passions include music and cooking, often linking them; "Sweet time Cooking magic" originated from kitchen songs with his father. He values emotional honesty, arranging Ito's song as a "love letter" and openly addressing familial conflicts. After resolving his feud with Hiro and family tensions, he regained his original lively demeanor.