TV-Series
Description
Jin Tadokoro is a former student of Sohoku High School, where he was a key member and the vice-captain of the bicycle racing club, serving as its ace sprinter. Physically, he is the tallest member of his team, possessing a heavily built and imposing frame. He has straight, short black hair and small, sharp brown eyes. His large physique is notably due to his abnormally large lungs, which have a capacity of 8500 cubic centimeters, significantly higher than the average person.

Tadokoro's journey to becoming a successful cyclist was not straightforward. During his early years in middle school and his first year of high school, he struggled immensely, particularly with climbing. He often finished in last place and was forced to drop out of a training camp. His initial response was to try dieting to lighten his body, but this only deprived him of necessary energy. Frustrated and heartbroken by his inability to win, he reached the point of attempting to resign from the club. His path changed when the then-captain, Kanzaki Tooji, convinced him to focus entirely on his natural talent for sprinting and to worry about other skills later. With the captain's personal training and the support of Coach Pierre, Tadokoro found his calling and became a vital member of the Inter-High team by his second year.

His personality is as large as his stature. As a sprinter, Tadokoro is loud, confident, and immensely proud of his abilities. He is known to boast about his victories and will not hesitate to challenge anyone, including his own teammates, in a contest of speed and strength. This is most evident in his constant, fiery rivalry with his underclassman, Shoukichi Naruko, over who is the strongest and fastest. Despite his brash and sometimes intimidating exterior, Tadokoro possesses a deep caring and affectionate side. He is protective of his teammates, easily moved to tears by their struggles, and takes on a caretaker role for younger members like Hajime Aoyagi and Junta Teshima, whom he personally mentors. He expresses his fondness physically, often clapping teammates on the back or embracing them.

His motivations are driven by a desire to win and a fear of showing weakness. His pride sometimes leads him to hide his physical ailments, such as racing while ill and dismissing his struggles as giving opponents a handicap. He can be easily offended and holds grudges, as demonstrated when he punched Hakone Academy's captain, Juichi Fukutomi, for causing an accident that injured his own captain, Shingo Kinjou. However, he is also capable of forgiveness, eventually accepting a formal apology and gift from Fukutomi. His strategic mind and experience are invaluable to Sohoku, and he plays a crucial role in pulling the team forward using his exceptional physique.

In the story, particularly during the New Generation arc, Tadokoro is one of the three veteran third-years, alongside Kinjou and Yusuke Makishima. He serves as a bridge between the previous generation and the new first-years, including Sakamichi Onoda. While initially baffled by Onoda's otaku interests, he grows to respect the first-year's determination, even agreeing to sing the theme song of Onoda's favorite anime, Love Hime, to help him regain his confidence during a race.

Tadokoro is famous for his unique sprinting abilities. His signature technique, the Mach Speed Oxygen Human Bullet, utilizes his immense lung capacity. He takes a deep breath to feed his muscles a massive amount of oxygen, which reduces the build-up of lactic acid and fatigue, allowing him to accelerate explosively. He also employs his large body as a wind-blocker to lead the team, even on climbing sections, a skill honed from his failed attempts to be a climber himself. These talents have earned him nicknames such as the Human Bullet Train and the Rampaging Human Cannonball.

Beyond cycling, Tadokoro's family owns a bakery, which supplies bread to the school. He has a strong competitive streak that extends beyond the bike; he is a master of kendama and a speed-eating champion, holding a record for finishing an extra-large bowl of ramen. After graduating from high school, he attends Tsukushiba University and continues to race for its cycling club.