|Age (Rainbow Live)||15-16|
|Age (King of Prism)||17|
|Current Residence||Tokyo, Japan|
|Romantic Interest(s)||Suzuno Ito|
|Hair Color||Ash brown|
|Eye Color||Olive green|
Over The Rainbow (Episode 51)
|Relative(s)||Natsuko Mihama (Mother)|
Takeyuki Mihama (Father, deceased)
Kouji is usually kind and soft-spoken but is actually easily angered according to Hiro. Kouji can be very strict but he also has a very caring and motherly personality, which he often displays to those he cares for, including his mother and girlfriend. He has a somewhat mysterious and unpredictable behavior but ultimately has good intentions. He has a passion for music and cooking.
Kouji is a tall boy with olive green eyes and shoulder-length dim gray hair. He wears a dog tag which belonged to his father: Takeyuki Mihama, and a purple matching Over The Rainbow bracelet with Hiro and Kazuki. In King of Prism, his hair grows out longer and he ties his hair into a small ponytail.
Role in the Plot
When Naru is troubled after being forced to perform her own "My Song", she immediately thinks of Kouji and his songs she heard on the roof. She asked him to give him one of his songs, to which he sternly refused. Naru returned later to apologize to him, realizing that each song is special to an artist. After hearing her touching words, Kouji changes his mind about the girl and decides to write her a song. He promises he will deliver it to her before the Prism Show begins the next day. Although Naru's co-workers do not believe that he will come, Naru believes, and he rewards her patience with her first "My Song". As he leaves the shop, he sees a rainbow across the sky.
When Naru fails to perform her song and cries, Kouji sings for her, prompting her to see the colors of the song she couldn't before, ultimately ending with Naru's three jumps. Kouji, who was with Hiro, says that he 'won't run away any more', and leaves Hiro aghast.
After meeting Naru, Kouji seems to be more open. However, a while after their first meeting, Kouji watched Ito doing a Prism Live. He looked quite surprised and it seemed to have an effect on him. After the show, he tells Ito that her song was very intense.
Later on, Kouji is playing at a park nearby and Naru decides to go with Ito on their lunch break. They watched until the presentation was done and then came to talk with Kouji. Though, Hiro, that had been there since the beginning, interrupted their conversation and asked for the song Pride that Kouji had. But he refused somewhat angrily and walked away. Hiro then invited both of them to eat and asked Ito to compose for him in exchange for money. Ito accepted after thinking of the guitar she wanted to buy.
Later on, Naru calls Kouji and tell him that Ito will compose a song for Hiro. Kouji is shocked and goes to Ito's house to try and change her mind, as he feared that Hiro would do the same thing to her as he once did to him. But being stubborn, Ito refused and ordered Kouji to leave.Then, the song Ito made was ready but before she could give it to Hiro, Kouji gave the song Pride away. Hiro then made his debut with Pride and steals the credits from it, saying it was his instead of Kouji's. During the Try Groovin' Session Kouji arranges Ito's song that she was supposed to give to Hiro which leaves her angry. Kouji explains to Naru and Ann that it was a love letter for Ito. Upon hearing this Naru immediately tells it to Ito. Ito chases Kouji, which leads Naru crying (Rinne comforting her) revealing she had feelings for him. Kouji confesses his love for Ito and kisses her in the park. The two begin to date.
A few days later, Kouji's mom finds out that Kouji and Ito are a couple, and is horrified. After Naru's concert for the children, Ito's partner for the duo competition is Otoha and they ask help from Kouji. As a result, Kouji visits Ito's house, and her father wants him to leave immediately after discovering his true identity. He hears this and leaves, but Ito becomes worried. Later, they met again, but this time, hearing the whole truth about their family's history. The couple became shocked and terrified upon hearing this terrible fate. Natsuko doesn't want Ito and Kouji to be together or she will remember the incident. Ito leaves as fast as she can, trying to avoid Kouji. In the end, Ito chooses to break up with Kouji. However, after they sort things between them and their family they began to date again.
King of Prism
In King of Prism, Kouji seems to have gotten back his original lively personality, since his fight with Hiro had ended and the conflict in his family had been solved. He takes the offer to write the soundtrack for a Hollywood movie in America to help repay Edel Rose's debt.
- He is the youngest member of Over The Rainbow.
- He is in charge of designing the costumes for Over The Rainbow.