Jun Shibaura was twenty-one years old. He was a third year student at Meirin University, and he belonged to the Netgame Club "Matrix". A self-proclaimed (for good reason) genius, he decided to demonstrate it by creating a game wherein people played in their own minds, or something like that. His father is the president of this enormous company and keeps Shuichi Kitaoka on retainer for emergencies such as his arrogant son.

After he became a Rider, he set up his game with rules like the Riders fight by. Last one standing wins. I can't imagine he had any difficulty getting the rest of the club to go into it. A young woman stumbled upon two of the players fighting and fled. But when people came to investigate, it was as though nothing had been there. Fighters, who disappeared, it drew Reiko because it seemed related to her vanishing people investigation. They almost met Jun when they investigated the Netgame Club. A group of boys who had no interest in anything outside their games who wouldn't even look at them. But Shinji discovered the rules of the game and it was too like the Kamen Rider battle for him to ignore. Eventually he actually met Jun, who out-arroganted Kitaoka without nearly the justification. It quickly proved that, while in the regular world he was physically weak, he had bound Metalgelas. He was enormously powerful. Unfortunately he just didn't realize that so were the other riders. It was all a game to him, and a lot of fun. He managed, by dint of Shinji hesitating, to injure our boy and made off with his Dragredder card, reducing Ryuuki to blank form. He spent some time tormenting Shinji, threatening to destroy his card. He managed by dint of major computer hacking to place himself in charge of Ore Journal. Their talented computer expert, Shimada, eventually managed to wipe out his programming and free them all from his nasty control.

Sometime during all that he got picked up by the police, and his father sent Kitaoka to get him out. In the meantime, Kanzaki chose Asakura to be Oja. Thus we got quite a bit of overlap as Jun went from not having met other Riders, to knowing the identities of five of them as proximity brought him to discover who Knight, Ryuuki, Zolda, Oja and Raia were. Oh, he enjoyed that. He managed to force a few major battles with all of them involved. Eventually Raia was able to retrieve the Dragredder card from Gai and return it to Shinji. While they managed to prevent Gai from killing Knight, later events led to his final battle.

Gai fought Knight, while Raia and Ryuuki tried to stop them. Oja and Zolda were deep in battle. In close proximty, the fights soon overlapped. Zolda used his Final Vent against Oja, and then walked off. But Oja had grabbed Gai and put him in its path. Recovering from the impact, Gai was most indignant. Unfortunately he was also an idiot. Oja turned and destroyed him. It was pretty definite that Shinji was about the only person who felt saddened by his death.