Seishiro Nagi

Nagi is a tall young man with a slim but muscular build. He is shown to have medium-length white hair that leaves a V-shaped fringe between his eyes. He has grey eyes with large irises. In high school, Nagi wore a school uniform consisting of a white jacket with a cascading star print on the collar, though underneath he wore a dark hoodie instead of a dress shirt and tie. He also wore dress pants and shoes. In Blue Lock, Nagi wears the standard body suit (black with grey stripes) and tracksuit. During the first selection, she wore Team V's number 11 jersey, and during the second selection, she wore Team White's number 7 jersey.

Nagi is a very lazy and unmotivated person with an outstanding aptitude for soccer. He is preternaturally talented, with uncanny reflexes, good speed, and jumping skills. But at first he has no interest in turning pro or even playing the game. As long as he can get a decent job and continue living a laid-back life, he is content to do nothing forever, and often appears lethargic in his speech and body language. Introverted to a fault, he lives alone in an apartment his parents pay for with only a pet cactus for company. He was shown to have no friends in high school before meeting Reo, and was frequently talked about or possibly bullied. Even so, he shows no interest in socializing, and often has to be dragged into things by others, especially Reo. He initially does not want to put in effort in soccer, and looks down on those who are weak and untalented at the game, as such things come easily to him. He doesn't even know anything about the best soccer players in the world, much to the chagrin of his competitors. At first, he is shown to be indifferent to playing soccer and becoming the world's best striker, preferring to play video games or skip training altogether. He displays hermit-like behavior and can actually be addicted to his phone. He has a hard time parting with it when Anri tries to confiscate his items, and Reo is even able to bribe him into playing when he reminds him that he can get it back with the goal reward system. Despite all this, Nagi proves that he can be motivated by a challenge. Upon entering Blue Lock, he encounters players who make him so invested in the game that he is willing to create his own strategies and go against Reo, whom he normally obeys, just so he can think as little as possible.

Nagi also has a daring side that comes out more often when he's around Baro due to an early rivalry that started when he called him Reo's "slave." He often opposes him and stands up to him when his arrogance irritates him, something very few characters are willing to do given how intimidating Baro can be. But when he wants to play, he demonstrates a deep sense of teamwork and can create synergy with many players, Reo and Isagi in particular. Although Nagi seems like an apathetic person, he is a reliable player who has some of the most unpredictable moves on the field, perhaps only rivaled by Gagamaru in terms of creativity. Nagi seems to care about his friends and teammates, especially his best friend Reo, though their relationship becomes rocky starting with the Second Selection due to Reo's possessiveness towards Nagi, which clouds their vision of their shared dream of winning the World Cup. However, deep down he is a selfish man like some of the best Blue Lock players. He only cares about his ambition, his dream and winning. Nagi tends to clash with people she dislikes. When she meets Baro after Nagi and Isagi's loss to Rin Itoshi, they immediately begin arguing and provoking each other, competing on the field over who is the better of the two, frequently challenging each other in 1v1s, throwing insults at each other, and even fighting over who gets the single bed in a three-member team room.

Talent Archetypes Forwards: Also known as strikers, their main objective is to score goals. They are usually the players who receive the most attention since their role is designed to be in a goal-scoring position. They also participate in penalty and corner kicks when the opposing team kicks the ball out of the field. They are usually the players in charge of starting the match at the beginning and at half-time. Creative Midfielder - Creative midfielders are players who can create goalscoring opportunities for the team, often in situations where nothing seems likely. They typically have good ball control, passing ability and movement, and will be blessed with vision and ball intelligence. With Nagi’s perfect ball control, flexible movements, and technical skill, he can bring even the most difficult or hopeless plays to life. He alone has scored the most outrageous goals in Blue Lock due to this ability, and he continues to evolve into a creative playmaker. After training with Manshine City and better understanding his strengths and weaknesses, Nagi is much stronger physically, has more refined ball control and ball handling, and personally takes the initiative to create his own plays rather than simply being a part of someone else’s. Skills Perfect Ball Control - In football, having control of the ball is of great importance to all levels of player. The ability to control an oddly bouncing ball quickly and effectively gives the player with the ball an immediate advantage. The first touch is often the difference between success and failure in most situations during the match. Nagi has exceptional ball control and consistently demonstrates this by setting traps and scoring with near-exact accuracy. He consistently scores high-level shots.