First Manga Appearance: Chapter 25
Name Meaning: Kama=sickle, Jun=pure; innocent
Gangs: Kamakura Mad Dogs; Oni-baku Gumi
Homeroom Class: 1-C; 1-F (repeated)
Previous Schoola: Tsujido High School; Kamakura P. S. 5
Transportation: Honda Steed
Penis Size: Baby tadpole
Notable Features: Half-American, half-Japanese; plays guitar
A half-American, half Japanese, he grew up in Honmoku with his mother & brother, Kaoru, while his father was in the navy. Around the age of 12, he befriended his next door neighbour, Natsu & they quickly became close friends. Using a broken radio as their amp, he would play guitar over Natsu's bass & Natsu's sister, Fuyuka, would sing. Kaoru was often jealous that he was over at Natsu's house so much. Natsu often spoke to him about the "American Dream", in which they would go to L. A. & start a band. Fuyuka gave them new guitars to support their dream.
Fuyuka thanks him for being such a good friend to Natsu, making him a better person. One night, Fuyuka failed to come home after shopping & Kamata went looking for her with Natsu. They found her just 50 feet from their home, raped by a gang. Fuyuka committed suicide by jumping in front of a train the next day. Natsu plans to kill Fuyuka's attackers & escape to America. A cold-feeted Kamata arrives with some adults to stop Natsu & finds his friend covered in blood surrounded by dead bodies. Natsu calls him a traitor as he is taken away.
He moves to Kamakura when the Honmoku house was torn down. He regretted his decision & never touched his guitar again. He would get into fight after fight as if he was trying to hurt himself, earning the title "Mad Dog". He taught his brother to fight because Kaoru was often picked & getting mistaken for a girl. He is constantly embarrassed by his younger brother's cross-dressing "Pretty Pincher" scam & tries his best to deter Kaoru.
He attended Kamakura P.S.5 with his friend, Saejima & gained fame in during 8th grade. Becoming arrogant from their newfound fame, they got beaten on the street by some 9th graders & went after them for revenge. He first used pencils as a weapon on the 9th grader's leader. They were widely feared after that incident. After graduating, he attends Tsujido with Saejima.
After a period of suspension for fighting, he returns to Tsujido with Saejima & begins targeting the Oni-baku after hearing of their strength. They attack all those in league with the Oni-baku, including Tsukai, Abe & Makoto. After capturing Ryuji, he mercilessly attacks Ryuji, who counts all his punches. He later fights Ryuji, who has escaped his captors & pays him back for every punch. Despite getting saved by his senpai, Takada, he charges at Ryuji & is knocked back. He is eventually beaten by Ryuji, while Saejima is beaten by Eikichi. The Kamakura Mad Dogs accept defeat & befriends the Oni-baku.
He is later invited to the Oni-baku's plan to get laid with Itou Yui & her friends by Saejima but declines, stating that he is done with chasing women. He tries to stop the Oni-baku Gumi from going after the new blonde girl, Kaoru, upon recognising her as his sister. He gets beaten up by the Oni-baku Gumi, who still go after Kaoru despite his protests. He reveals Kaoru's secret the following day to everyone except Eikichi, who won the competition & claimed Kaoru for himself.
During the Fumiya arc, he defends a fellow Tsujido student who is targetted by Fumiya Kyokuto High. He is stabbed in the back by Fumiya when he turns to leave. He struggles to find Ryuji to warn him of Fumiya & is taken to hospital. He & Saejima later escape to aid Ryuji against Fumiya, only to find Fumiya has already been beaten. He tries to restrain an angry Saejima from attacking Fumiya when Fumiya arrives to apologise to Ayumi.
During the Okubo arc, he recognises Okubo as a murderer & offers Eikichi money for Okubo's extortion. He arrives as backup during Eikichi's fight with Okubo & prevents Okubo's men from fighting dirty. Sometime later, he offers Makoto money after hearing of Makoto's girlfriend, Mami's pregnancy & assists him against Mami's father, who disproves of the marriage. He helps fight of Mami's father's men, allowing Makoto & Mami to escape, until Mami discovers that she isn't really pregnant.
He is held back a year & ends up in the Oni-baku's class, 1-F, in which the homeroom teacher is the brutish Minamino Youka. However, he remains absent from school & misses out on the whole Minamino incident. He & the Oni-baku Gumi is later targeted by the 1st years in 1-F, known as the K. T. Butai but easily defeats them with Saejima. The K. T. Butai's leader, Katsuyuki, turns out to be the Oni-baku's friend & is beaten up for causing trouble.
He later gets introduced by Moro Hiro to the awesome psychic powers of Kiyoma from Tsujido with Saejima & Tsukai. He beats up Moro Hiro upon finding out the limitations of Kiyoma's power, annoyed that a big deal has been made of it. He later makes sure that no one helps Makoto, who has gotten into trouble with his big mouth & using the Oni-baku's fame. During the Midnight Angel arc, he & Abe stop Katsuyuki from fighting Tamura & the Kamakura Massacre Unit, warning Katsuyuki that he would've gotten beaten easily.
He watches Ryuji with Tsukai to prevent Ryuji from going after Akutsu on his own. He later backs up Ryuji with the Oni-baku Gumi to prevent Akutsu's Midnight Angel from fighting dirty. They instead clash against Kamishima & the Kamakura Massacre Unit, part of a plan by Akutsu for the 2 groups to take each other out. He gets challenged by the Kamakura Massacre Unit vice chief, Takasugi, & takes him down with ease. Struggling to fend off their opponents, the Oni-baku Gumi are attacked from the darkness by Akutsu's Midnight Angel & the fight is interrupted by the police.
During the Yokohama Calvary arc, he rides to Yokohama by chance & spots Natsu. He visits ex-members of the Natsu's band, Vebejail, where he discovers Natsu's terrifying history with them. He searches for Natsu to settle their past & witnesses Natsu pushing an ex-member of Vebejail off a roof. He confronts Natsu, who walks off without a word. He goes to find the Music Master where he finds out Natsu's affiliation with the Yokohama Calvary. They are interrupted by Kaoru, who leads them to the fight between Eikichi & Natsu. He begs Natsu to stop, who states that he is still living in the nightmare of their past.
He goes after the Yokohama Calvary leaders, Nakagaki & Mauchi, beating down whole groups of Yokohama Calvary mobsters asking for their leader's location. He is pursued by the Yokohama police for taking down the gang & eventually finds the two leaders. He gets attacked by Nakagaki with a taser & drugged with a high dose injection of alcohol. He is held captive as bait, allowing Nakagaki & Mauchi to take out the Oni-baku as well as Natsu. He is held over the top of a building as a threat to Natsu, but to everyone's surprise, Natsu states that he has no friends & leaves.
He is used as bait to lure the Oni-baku into a trap set up by the Yokohama Calvary. As the Oni-baku begins to single-handedly overcome the Yokohama Calvary, Mauchi holds a blade to his neck, threatening the Oni-baku to give in. Eikichi states that Kamata isn't a weakling & Kamata attacks Mauchi, breaking free. However, he is knocked into a car, which is heading over the edge of the dock into the ocean. To his surprise, the car is stopped by Natsu, who arrives to save Kamata.
Natsu tells him that he told him to be left alone as everyone around Natsu usually ends up dying. Natsu reveals to Kamata that he never once forgot about him. As the two former friends smile at each other, Natsu is shot in the back by Nakagaki as he helps Kamata up. As Kamata breaks down & cries out in anguish, Natsu reminds him about their "American Dream". Natsu continues talking about their childhood with his last breath & dies as a crying Kamata begs him to wake up.
An angry Kamata beats down Mauchi as Eikichi beats down Nakagaki. Kamata heads to Natsu's place to find a chequebook & remembers that Natsu had told him he created an "American Dream" account & notices that Natsu had been continually putting in money all these years. At Natsu's grave, Kamata plays Natsu their song. He tells Natsu that they will go to America to fulfil their dreams & asks Natsu if he will be joining him. He leaves for New York with the Music Master to fulfill his childhood dream.