Nagi Seishiro is the star and top scorer of Blue Lock's TEAM V. At the time of entering Blue Lock, he was ranked 221st and is a genius striker who scored 7 out of his team's 18 goals. Other members of the soccer club include Isagi Yoichi, Chigiri Hyoma, Itoshi Rin, Bachira Meguru, Barou Shoei, and Mikage Reo. The soccer club is highly popular, and Nagi is no exception. He stands 190cm tall and has blood type O. He is a handsome boy with shaggy white hair and black eyes. Because of his cute and youthful face, his large physique isn't immediately obvious, but he is actually very big. Mikage Reo, who first discovered him, sensed his soccer talent just by looking at his build. He lives with his parents. His catchphrase is "What a pain." A quintessential slacker who finds everything bothersome, he always looks sleepy and even finds chewing and swallowing food a chore. He usually idles away his time playing smartphone games. When first selected for Blue Lock, he hesitated to participate because he wouldn't be able to nap or play games. During the tag test and the first selection, he often tried to slack off, causing trouble for Reo and Tsurugi Zantetsu. However, he is the type to deliver when it counts. He attends Hakuho Academy, a prestigious preparatory high school, and despite sleeping through every class, he is smart enough to rank 2nd in the entire school. He survived until the end in Blue Lock, and over time, he began to develop his own ego and skills without being told to by others. Despite being a slacker, he is surprisingly thorough about personal hygiene and life management. He washes his clothes and bathes frequently, and he keeps his room clean using a robot vacuum. His tone is lethargic, but he can be surprisingly blunt or foul-mouthed. When Barou Shoei acted selfishly, he remarked, "Did that guy leave his sense of cooperation in his mother's womb?" However, once he finds something he likes, he tries to treat it as the most precious thing in the world. Nagi Seishiro is evaluated as one of the greatest geniuses in Blue Lock. Despite having played soccer for only six months, Ego Jinpachi described him as a "brilliant talent," and he stood in TEAM Z's way as the strongest striker of the 5th stratum. His greatest weapon is trapping at a level impossible for normal human physical ability. He acknowledges his own unrivaled trapping skills and actively utilizes his talent. A single play from him can change the flow of a match and create numerous goals. Later, through small-sided futsal matches that emphasize individual play, he grows even further, showcasing playstyles closer to magic than soccer—controlling the ball freely with a single touch, letting a ball flying from behind slip past, or lobbing a spinning pass over a defender's head. In his current school, he is a celebrity known by almost everyone. Part of it is being the soccer club ace active in national tournaments, but thanks to his 190cm height, striking white hair, and indifferent yet neat aura, eyes follow him whenever he walks down the hall. During breaks, students gather in front of his classroom just to catch a glimpse of him, and even students in other grades know his name. Receiving confessions every semester is common, and his locker and desk are filled with gifts and letters on Valentine's Day. On days when many people gather, like school festivals or sports days, the area around the soccer field gets exceptionally crowded just to see him. However, he himself finds all that attention to be a total pain.