Mizuiro Kojima

is a student in Karakura High School and is in the same class as Ichigo Kurosaki.

Appearance
Mizuiro has shorter black hair, parted down the middle with a stray bang in his face and the tips fanning out. He looks very young and wears the Karakura uniform with the jacket zipped up.

Personality
When Mizuiro first met Rukia Kuchiki, Ichigo warned her that he was sly with the ladies. Mizuiro countered by saying he prefers older women, Ichigo comments that Rukia should be careful, which leaves Mizuiro confused. Mizuiro seems to be recourceful, level-headed and calm even in detrimental circumstances. These traits allow him to think straight and plan contingencies way ahead of time. He also likes to tease his classmate and friend Keigo by calling him "Asano-san" (Mr. Asano in the English dub), when he is overreacting, which makes him even more agitated. Despite his cheerful appearence he can be quite cruel, shown by not accepting his own mother. In fact, as Keigo mentions late into the series, Mizuiro is good at "putting up walls" and the only person he ever really opened up to is Ichigo.

History
Mizuiro went to Hiragi Junior High, along with Keigo. He met Ichigo and Chad on the first day of High School. Mizuiro went up and introduced himself to Ichigo and Chad despite Keigo telling him "Kurosaki and Sado" were rumoured to be "hoodlum bullies from hell". Mizuiro reasons that if it is only a rumour then it might not be true. Because Mizuiro introduced himself to Chad and Ichigo, hoodlum who were fighting with Ichigo turned on Keigo and Mizuiro. As Keigo was being stumped on the back, Mizuiro explained who he was to Ichigo and praising him a great deal in the process. Ichigo noted how unusual it was for a guy to praise his friends like that and asked Mizuiro if he was good at coming-up with excused. Mizuiro answered in the affirmative and so Ichigo tasked him to come-up with a good excuse so that he and Chad were not suspended for saving Keigo. As Ichigo rushes off to save Keigo, Mizuiro notes that he is filled with a feeling of happiness, noting that communication has been established.

Agent of the Shinigami arc
Mizuiro is first seen in Karakura High School, explaining to Tatsuki and Orihime, that Ichigo might not come to school a burgler attacked his house the night before. He says assures them that no one was hurt but Ichigo was need to help clean-up the mess. When Ichigo turns-up to school later that day, Mizuiro reminds Ichigo that they have social studies for 3rd period. They are interrupted by Rukia, who Mizuiro introduces as a new transfer student. Ichigo is shocked at Mizuiro's declaration but Rukia prevents him from causing a scene.

Bount arc (anime only)
Note:Events occurring in this arc are only in the anime and do not constitute canon material.

After Ichigo punches Keigo, he walks up to Mizuiro and greets him. The two of them then walk into their classroom and greet their classmates. After noting that Ichigo and Sado got tans, Keigo walks into the room and asks them if they went off somewhere together. He then asks them if they had some summer camping romance and Ichigo punches him yet again, telling him to keep his imagination in check. He then runs off crying.

A few days later, Mizuiro and the others greet Rukia when she returns to do battle with the Bounts. A while later, Mizuiro shows Keigo that he has aquired two tickets to a show, but says he has a date and can't make it. He hands the tickets to Keigo instead and asks if he can get someone else to go with him. Before they can continue, Ririn detects the presence of Ryo Utagawa and Ichigo's group leaves to confront him. Keigo whines about being left out, which causes Mizuiro to comment that Ichigo and the others just don't like him, much to Keigo's chagrin.

Arrancar arc
After Rukia cheers up Ichigo (albeit somewhat violently) after his defeat by Ulquiorra Cifer and Yammy Riyalgo, Mizuiro is shown calling Keigo "Asano-san" which drives Keigo hectic. They than notice Toshiro Hitsugaya's team causing chaos in their class. Unlike Keigo, Mizuiro does not interact with the Shinigami group, and after they leave, comically steps on Keigo, telling him "you[Keigo] make a superb foot-rest, Asano-san", to which Keigo angrily says he will kill him.

Later that night, Mizuiro is seen talking on his cellphone with an unnamed friend. He threatens to leave Keigo behind if he doesn't stop talking. Just than, Keigo spots a weird flying creature in the sky, but this only makes Mizuiro want to leave the former behind all the more, still calling Keigo "Asano-san".

The day after Orihime Inoue is kidnapped by Ulquiorra, Mizuiro and Keigo welcome Ichigo back to school after a long absence (due to the latter's training with the Vizard and his second fight with Grimmjow Jaegerjaquez). Mizuiro once again stomps on Keigo and offers Ichigo tickets to a Winter concert. After a long pause, Ichigo agrees to go. He is than confronted by Tatsuki about his fights with the Arrancar and asks what he has been doing. She than becomes violent when he refuses to tell her anything about it. As Tatsuki continues to scream her lungs out, Ichigo tells Mizuiro and Keigo to look after Tatsuki and also to stay far away from him. Later that evening, Mizuiro and the others secretly follow Ichigo to the Urahara Shop and witness his as well as Uryū Ishida and Yasutora Sado's departure to Hueco Mundo.

A while later, Keigo asks Mizuiro to join the Karakura-Raizer Team, but Mizuiro rejects the offer, albiet with a cheerful expression on his face, highly implying that he doesn't believe the story about his friend witnessing the attack on Don Kanonji. Instead, Chizuru Honshō, who overheard the conversation, joined instead.

Fake Karakura Town arc
He was later found huddled together with Chizuru by Keigo, and were later joined by Tatsuki, and Don Kanonji after barely escaping a direct confrontation with Aizen (mainly due to Matsumoto's timely intervention). It was revealed that Mizuiro was among the first individuals to awaken after the entire town was transported into Soul Society, and took the liberty of preparing contingencies ahead of time, salvaging emergency supplies from the dormant town and its stores, which included food, useable batteries for his mobile phone, and a few stun guns for self-defense. When Tatsuki told them of what happened with Aizen, Mizuiro only calmly surmises that the weapons he acquired won't do much against an opponent like Aizen, and then opted to discard the stun guns instead. When Chizuru demanded an overall exlaination as to what is going on, Aizen's spiritual pressure suddenly loomed over to them, alerting the group of his presence. As they rise to run for their lives, Mizuiro in his usual calm state, while sporting a vapid expression on his face, only proceeded to pick up a bottle from a nearby bin. When Aizen blocked their path, Mizuiro was the first to make his move by throwing the bottle he had picked up earlier at Aizen's direction, only to disintigrate after coming into proximity. Noting that effect in a level-headed manner, Mizuiro then tried a different approach, and allowed a cylindrical canister expelling flammable gas at one end roll towards Aizen. After ushering his friends to distance themselves away, he ignited the gas engulfing Aizen and the area he's in by throwing a live cigarette lighter, causing a huge explosion to ensue

Trivia

 * In the official character book, part of his description says 'He has a cute face, but he's actually a ????'. At the moment, Tite Kubo has not said anything about this blanked out word, leaving it unidentified.