Wataru Kuon entered the Blue Lock program as a former member of Team Z. His football journey began in high school, where he founded a school club with friends fueled by shared dreams of reaching nationals. However, his teammates gradually lost motivation and abandoned serious pursuit of the sport, leaving Kuon disillusioned and isolated. This experience cemented his belief in prioritizing individual survival within competition, driving him to accept the Blue Lock invitation with a vow to win alone. Within Blue Lock's First Selection, Kuon initially emerged as Team Z's primary strategist. He devised tactics such as the "I'm the next 9" approach and the "3x3 all-stars" formation to unify the team. He identified his key weapon as an exceptional 68 cm vertical jump, which maximized his effectiveness in headers and goal-scoring. His leadership and communication temporarily earned his teammates' trust. Kuon's defining moment arrived during Team Z's critical match against Team W. Facing potential elimination and convinced of Team Z's impending loss, he secretly negotiated with the opposing Wanima brothers. He traded Team Z's strategies and player weaknesses in exchange for a personal guarantee of scoring three goals, securing his advancement regardless of the match outcome. This betrayal was exposed mid-game, shattering his cooperative facade and revealing his ruthless commitment to self-preservation over team loyalty. Despite this betrayal, Kuon later contributed indirectly to Team Z's victory in their final First Selection match against the formidable Team V. Initially refusing to participate, certain of defeat, he witnessed his former teammates' tenacity and evolving skills during the match. This rekindled his passion for football, prompting him to offer tactical support and encouragement from the sidelines. His assistance aided in securing Team Z's win, though he acknowledged his prior actions had permanently fractured their trust. Kuon advanced to the Second Selection but was eliminated during this phase. Personality-wise, Kuon typically presented a friendly, cooperative demeanor that effectively masked his underlying pragmatism and deep distrust of teamwork. His high school experience instilled a fear of being hindered by others, leading him to view cooperation within Blue Lock as naive. While capable of genuine dedication when personally invested, his instinct for self-preservation frequently dominated, resulting in manipulative actions. Following his exposure as a traitor, he displayed ruthlessness and openly dismissed Team Z's cooperative efforts as foolish.