Rensuke Kunigami is a 17-year-old Japanese male from Akita Prefecture, standing 188 cm tall with a muscular build, bright spiky orange hair in an undercut style, and auburn eyes. He grew up with parents, an older sister, and a younger sister. Childhood isolation from male peers, stemming from playing primarily with his sisters, culminated in a violent incident where he defended his sister against bullying classmates. This event prompted his family to channel his physical strength into soccer from age six, forging his "fair and square" motto and deep aversion to unfairness. Initially, Kunigami exhibited a moral and serious personality underpinned by a strong sense of justice, serving as a stabilizing "big brother" figure within Team Z. He balanced football passion with rationality, though this led to clashes with stubborn teammates like Raichi. He expressed visible embarrassment when praised and sincere gratitude for recognition, sharing goal rewards such as steak with teammates like Isagi Yoichi after collaborative plays. His primary motivation centered on becoming a "football superhero"—inspired by idols Didier Drogba and Olivier Giroud—aiming to inspire others through heroic plays rather than pursue personal glory. Kunigami's football strengths focused on his powerful left-footed shooting and superior physique. His signature moves featured accurate mid-range shots within 28 meters and knuckleballs from nearly 40 meters, using his physicality to shield the ball and overpower defenders. During the First Selection, he emerged as Team Z's top scorer, netting crucial goals against Teams X and V; against Team V, his two goals—one a long-range knuckle shot—helped secure victory. In the Second Selection's 3v3 matches, he scored a header and a physical close-range finish despite his team's loss to Isagi, Nagi, and Barou's squad. His collaborative approach increasingly conflicted with Blue Lock's emphasis on individual ego, particularly during a loss to Ryusei Shidou's team. Eliminated after Reo Mikage was selected over him, Kunigami chose the mysterious "Wild Card" path instead of leaving the facility. The undisclosed trials of the Wild Card program reshaped Kunigami physically and psychologically. Upon returning after the U-20 match, he exhibited a colder, detached demeanor, with longer hair, increased muscle mass, and minimal interaction with former allies like Isagi. His playing style shifted toward individualism; he prioritized personal goals over teamwork, dismissed others' contributions, and adopted offensive remarks. Football-wise, he developed ambidexterity, enabling shots and dribbles with both feet—particularly favoring his strengthened right foot—and refined his physique to near-professional specs comparable to Noel Noa's. New techniques included the "Rush Volley" and "Shot Fake - Cut In," enhancing his threat as a clinical finisher. Despite his abrasive exterior, he retained underlying morals, refusing to teach Isagi ambidexterity to avoid compromising the latter's development. Qualifying for Japan's U-20 World Cup team after the Neo Egoist League, Kunigami continues pursuing his striker ambitions with a focus on dominance. His journey reflects a transformation from an idealistic team player to an isolated competitor, yet his core drive—to "fight against the world fair and square" for his dream—persists throughout this evolution.