Teppei Kiyoshi, a third-year student at Seirin High, founded its basketball club. Standing 193 cm tall and wearing jersey number 7, he earned recognition as one of the "Uncrowned Kings" with the title "Iron Heart" for his exceptional defensive resilience and leadership, though he personally dislikes both the title and nickname. Raised primarily by his grandparents, Kiyoshi began playing basketball at Shōei Junior High after encouragement from a teammate named Taichi to leverage his height, which he had previously viewed as a hindrance. He quickly excelled, becoming team captain and leading his squad to a national top-four finish. His team faced a crushing defeat against Teikō Junior High and the Generation of Miracles, particularly demoralized by Atsushi Murasakibara’s dominance, leaving a lasting psychological impact. Upon entering Seirin High, he established the basketball club by persuading key members to join. He confronted classmate Junpei Hyūga, who had quit basketball, challenging him to a one-on-one match. After overwhelming Hyūga, Kiyoshi convinced him to rediscover his passion for the sport, solidifying the team’s core. He also recruited Riko Aida as manager through persistent requests. During his first year, Kiyoshi suffered a severe knee injury in a match against Kirisaki Daichi High due to a deliberate dirty tactic by Makoto Hanamiya, another Uncrowned King. Opting for rehabilitation instead of career-ending surgery to keep playing, he spent nearly a year hospitalized, taking up harmonica and card games (Hanafuda) as hobbies. He returned to the team after Seirin’s loss in the Interhigh preliminaries, mentoring the first-years and notably reconciling Tetsuya Kuroko and Taiga Kagami after their rift. He voluntarily relinquished his ace position to Kagami after losing a one-on-one match, prioritizing team strength over personal status. Kiyoshi plays center but also functions as a point guard due to his strategic vision and ball-handling skills. His signature abilities stem from his large hands: the "Right of Postponement" allows him to delay actions until the last second, enabling rapid shifts between shooting, passing, or dribbling, while the "Vice Claw" lets him secure rebounds single-handedly, making him a formidable defensive anchor and playmaker. Despite his knee condition, he endured brutal tactics from Kirisaki Daichi in a Winter Cup preliminary match, including targeted attacks by Hanamiya, to protect teammates and secure victory. In the Winter Cup quarterfinals against Yōsen High, he confronted Murasakibara again, using psychological tactics—such as questioning Murasakibara’s enjoyment of basketball—to disrupt his focus. Though physically overmatched, Kiyoshi’s resilience helped push Murasakibara to reveal his genuine passion for the sport. Kiyoshi values team unity over individual accolades, nominating Hyūga as team captain despite founding the club, believing Hyūga’s motivational skills better served the role. His relationship with Riko evolved from a past romantic involvement to a close friendship grounded in mutual trust; she supported him during his injury and respected his insistence on playing through pain. He prioritizes collective growth, often advising teammates to "enjoy the scenery" while striving for victory. After Seirin won the Winter Cup, he accepted medical advice to undergo surgery in America, ending his high school career. His final match participation in the "Last Game" against the Jabberwock streetball team underscored his commitment to team defense and strategy. Off-court, Kiyoshi is characterized by modesty, offbeat humor, and occasional obliviousness—traits his teammates label "airheaded." He enjoys dorayaki (sweet bean cakes) and fears rats and haunted places. Academically, he ranks in the top five of his class.