When Midousuji was a child, he lived with his relatives due to his mother being hospitalized for an unknown condition. Midousuji picked up cycling, and used his bike to get to and from the hospital as often as he could visit. During the summer, he'd make the 20km trip every day. His mother told him that he had beautiful teeth, and that it was important to have nice teeth as a professional athlete. Midousuji committed himself to becoming an athlete for this reason. However, he wasn't good at physical education or any of the sports at school, and he was bullied by his classmates as a result of being weak and incapable.
After winning a race and visiting his mother to share his results, Midousuji's mother's health declined rapidly within moments. Midousuji invited his mother to watch his race the upcoming Sunday, but fearing the worst, she told him to keep moving forward. She died soon after that. After his mother's death, he vowed to become a pro and to keep winning.
During a race in middle school, Midousuji went head to head against Imaizumi Shunsuke in a race. He falsely informed Imaizumi that his mother had died, causing him to fall a good five minutes behind Midousuji as he won the race.
A New School
Come high school, Midousuji joined the Kyoto Fushimi High Bicycle Club. Upon joining the team, he challenged (former) ace and captain Ishigaki Koutarou for his title as the ace and won, usurping Ishigaki from his position. Midousuji chose to form the Kyoto Fushimi cycling team around him as his disposable support for victory, while he would act as the team's ticket for winning the Inter High. Despite behaving like a dictator to the team, Midousuji didn't claim the position as captain and left that for Ishigaki.
Before the start of the race, Midousuji was interviewed at the stage as a participant of the Inter High. He stole away the microphone from the staff member and announced his intent to crush Hakone Academy, and to use the Inter High as a stepping stone for his greater success. Imaizumi approached the stage and promised Midousuji that he would get his revenge for the underhanded tricks he used during their middle school race, which initiated a conflict between the two. Their conflict was quickly ended by the intervention of Fukutomi Juichi, who told them to settle it during the race.
The first stage was mostly uneventful from Kyoto Fushimi's perspective. Midousuji's order was for the team to hang around the front of the peloton for the duration of the day. During this time, Onoda Sakamichi made his way from last place to catch up with team Sohoku. In order to reach Sohoku, he needed to pass the 100 cyclists that comprised the peloton. The 100th person was Midousuji, who wouldn't let Onoda pass without a dose of intimidation. As a consolation prize for his "desperation," Midousuji showed Onoda a secret technique of his: he leaned over the handlebars his bicycle and nearly hit the ground with his face in order to increase his speed and efficiency. Onoda surpassed Midousuji's expectations and passed him with incredible cadence. Midousuji decided then that Onoda wasn't the same as the other "mass-produced" racers.
It was also around this time that Machimiya Eikichi offered to form a pact with Kyoto Fushimi, claiming that Kyoto Fushimi and Hiroshima Kureminami had the same objective: to beat Hakone Academy. Machimiya offered to work together until only Hiroshima Kureminami and Kyoto Fushimi remained and after they'd beaten Hakone Academy through their combined strength. Midousuji never explicitly agreed to his terms, but decided that he would wait for Hiroshima Kureminami to prove their worth through their actions.
As aces Kinjou Shingo and Fukutomi Juichi launched from their assists, Imaizumi Shunsuke and Arakita Yasutomo, for the goal line of the first stage, Midousuji passed Hakone Academy and Sohoku to compete for the victory. While passing Imaizumi and Arakita, he showed Imaizumi that he still had "reserves" left to use that would make him even faster. Midousuji unraveled the taped-up fingers on his left hand, allowing himself the ability to shift his outer gear at will, and burst forth with incomprehensible speed. Using two of his secret techniques, Midousuji tied with both Fukutomi and Kinjou for first place on the first day.
Midousuji's plans calculated for Sohoku to crumble during the first leg of day two. With Tadokoro Jin falling behind due to health reasons and Onoda choosing to go back and help him, Midousuji's projection of the second day was going according to plan. Midousuji remained matched with Kinjou and Fukutomi until all of Hakone Academy assembled, and they pedaled ahead. Imaizumi reunited with Kinjou and asked how Midousuji planned to accomplish anything without his team.
The other members of team Kyoto Fushimi arrived, and Midousuji left Kinjou and Imaizumi in the dust. When he reached Hakone Academy, he challenged them to the sprinters checkpoint so that he could prove how serious he was at defeating them, and requested that they send somebody to race Kyoto Fushimi for the checkpoint. Izumida Touichirou offered, but when Midousuji revealed that he himself would be racing for the checkpoint, he became flustered in the face of Midousuji's intimidating aura. Shinkai Hayato, as Hakone Academy's ace sprinter, took his place with cool confidence. Midousuji planned to win against Shinkai to reduce Hakone Academy's morale and cause them to fall apart just as Sohoku did.
At first, Midousuji made it seem like Shinkai had him beat, putting on an act of screaming in disbelief and hanging his head. Just as they approached the spectator area, Midousuji's tune changed once more to his confidence in his victory. He sang some of the lyrics to a Japanese children's song called Furusato - a song with lyrics about chasing rabbits on a mountain. Midousuji heard a rumor that Shinkai had been traumatized after hitting a rabbit while passing a racer on their left, so he wasn't able to pass people on their left. Knowing this, he sprinted ahead of Shinkai before veering as far right as possible, leaving ample space for Shinkai to pass him on his left and even inviting him to do so.
Shinkai eventually broke through his own trauma through his "demon self," where his demeanor changed entirely, leaving Midousuji with no choice but to race him in earnest. By a slim margin, Midousuji won the checkpoint by swinging his bicycle in front of his body using his long limbs while sitting down.
Thanks to Shinkai's defeat, Hakone Academy split apart. Kyoto Fushimi took this time to reassemble and claim the climbers checkpoint and headed for the finish line, but not before taking "decisive measures" and dropping their sprinters - entirely Midousuji's choice, which also helped Midousuji and Kyoto Fushimi claim the mountain checkpoint as well in a dominating fashion. With the four Kyoto Fushimi members all finishing ahead of Toudou and Fukutomi.
Before he could make it close enough to the goal, Hakone Academy and Sohoku both reassembled despite Midousuji's expectations. Midousuji and his assist, Ishigaki, split apart from Kyoto Fushimi, and Midousuji launched from Ishigaki with good time and created a decisive margin between him and the other team's aces. Every time they approached, Midousuji pedaled harder. Just before the finish, he clacked his teeth together in a smile and his front tooth cracked. The shock of this gave Fukutomi and Kinjou the leverage they needed to pass Midousuji, and Midousuji ended the race in third place, with Fukutomi in first. The shock meant he was absent from the medal presentations.
That night, Midousuji informed the Kyoto Fushimi Bicycle Club that he was resigning and that he would be heading back to Kyoto. On his way back, he met with Onoda, who asked him if he liked anime. Midousuji offered to race him to the pharmacy up ahead: if Onoda won, he would talk with him about anime.
Midousuji won the race. He asked Onoda why he smiled during their race, and Onoda told him that he liked riding with his friends and that he found it fun. Midousuji called it gross and left, but changed his mind about leaving the team. In the middle of the night, Midousuji stopped at a restroom off the road and cut off his hair.
Just before the start of the race, Midousuji showed up near Kyoto Fushimi's tent area and surprised Ishigaki, who was searching for him. Midousuji arrived in time to start with the other aces, and Ishigaki quickly caught up with him to pull him. Hiroshima Kureminami never united with what remained of Kyoto Fushimi, and Midousuji considered that just as well: if Machimiya couldn't follow through, he'd be nothing but dead weight. He did correctly predict that Arakita would drop out of the race before anyone in the three schools.
The final climb came fast, and Midousuji demanded that Ishigaki pull him like his life depended on it until the base of the mountain, where he planned to drop him. Ishigaki persisted even up the base of the mountain and told Midousuji that he was genuinely happy to be his assist. After some parting words of encouragement, Ishigaki ran out of energy and dropped out of the race, leaving Midousuji on his own.
When Midousuji passed Sohoku and Hakone Academy, Toudou Jinpachi was being checked by Makishima Yusuke, so he sent Manami Sangaku to chase Midousuji and protect their ace. Instead of focusing on protecting ace Fukutomi, Manami challenged Midousuji to a race between them to see who could reach the aces first. Midousuji slipped in some terms about the loser being required to bow down to the other and let the winner take the goal, to which Manami agreed to without a single moment of hesitation, inciting Midousuji's intrigue. He sought the reason behind Manami's smile - it reminded him of Onoda's. Midousuji deemed Manami to be not gross because of his unrelenting mentality for reaching the peak first and because of his reason for riding: to "feel alive." In the middle of their competition, Onoda showed up and matched their speed without meaning to. This also incited Midousuji's intrigue. Manami, Onoda and Midousuji reached the aces at the same time, concluding their race in a tie.
Midousuji pedaled ahead for the goal, but Imaizumi blocked him. Midousuji was frustrated with how much personal growth Imaizumi had gone through over the three days of the Inter High, and no matter what he tried, Imaizumi wouldn't let him get ahead of him. Even though Imaizumi's bottom bracket was in bad shape, he still kept Midousuji in check until Midousuji wore himself out. Midousuji crashed on the side of the road and dropped out of the Inter High.
A medical car picked him up and Midousuji listened to the remainder of the Inter High from the radio. Midousuji knew that Onoda would beat Manami if only he started smiling, because he knew that Onoda was much faster when he was smiling. After the race was over, Midousuji slept in a medical tent for 18 hours straight.
After Inter High
Midousuji saw Naruko winning sprint races in his home track in Osaka, and went on to race against him, Mizuta and Yamaguchi, in which Midousuji offered to switch to Sohoku for the 42nd Inter High, but since he won, Naruko must become an all-rounder.