Seishiro Nagi

Nagi is a remarkably tall teenager. He has messy white hair that falls in a V-shaped fringe between his eyes, similar to Isagi's. He has gray eyes with large irises.

When he was in high school, Nagi wore a school uniform consisting of a white sports jacket with a cascading star pattern on the collar, though underneath he wore a dark hoodie instead of a dress shirt and tie. He also wore dress pants and dress shoes.

In Blue Lock, Nagi wears the standard suit (black with blue stripes) and the tracksuit. During the First Selection on Team V, he wore the number 11. During the Second Selection on Team White, the Third Selection on Team C, and the match against the Japanese Under-20 National Team, he wore the number 7. During the Neo Egoist League in Manshine City, he has returned to wearing the number 11.

Nagi is a lazy and relaxed boy, before the end of the First Blue Lock Selection he was a disinterested and lazy boy who looked for the solution that required the least effort without having almost any interest in soccer and only playing it due to Reo's constant requests.

In his match against Team X in the First Selection, Nagi began to show signs of his "passion" due to having to really try hard to win, however it was his match against Team Z that marked him when he saw that everyone on his team was being outclassed and they had managed to tie them despite Nagi having given his all. Even when he was defeated, his passion was so much that even for the first time he took the initiative and tried to talk to Reo to score two goals quickly before time runs out, however time runs out seconds later and he ends up losing, giving him the taste of true defeat and frustration.

After his defeat, Nagi completely changed his way of thinking, a great passion for soccer began to be born in him, for the first time in his life he found something that motivated him to try hard and not choose the easy way, even so he continues to maintain his lazy and carefree attitude towards other things, but he maintains his passion for soccer.

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 intelligence on the ball.
With Nagi's perfect ball control, flexible movements, and technical skill, he is able to bring even the most difficult or desperate plays to life. He has single-handedly scored the most outrageous goals in Blue Lock due to this ability and continues to evolve into a creative playmaker. After training with Manshine City and coming to better understand his strengths and weaknesses, Nagi is much stronger physically, has more refined ball control and takedown, and personally takes the lead in creating his own plays rather than simply being a part of someone else's.

Skills
Perfect Ball Handling: In soccer, having control of the ball is of great importance for all levels of players. The ability to control an awkwardly bouncing ball quickly and effectively gives the player with the ball the 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 constantly demonstrates this by trapping balls and scoring with near-pinpoint accuracy. He consistently performs top-level shots, especially in unfavorable positions, when under pressure from tough opponents. One of his most impressive feats is when he performed a fake volley shot. His ability to control the ball is rivaled only by Rin Itoshi and Tabito Karasu and is one of the few things that escapes Rin's logic. Due to his natural sense of controlling the ball with his own body, Nagi is a truly prodigal talent, being one of Blue Lock's best players despite having only recently started playing soccer, shortly before the show. After undergoing analysis from Chris Prince, Nagi understands the fundamentals of his ball control and has become more refined.

First-touch passing: Using his exceptional ball control, Nagi can use his first touch to make a creative pass to a teammate. Nagi often comes up with new ways to release the ball, whether it's with his chest or the tip, side, or heel of his foot. What makes Nagi such a creative player is his ability to turn any type of pass into a potential attack. No matter the quality or attributes of the pass sent to him, he can effectively pass it to a dangerous area. This ability has been demonstrated on numerous occasions, most notably when he controlled Isagi's difficult pass during the match against the Japan U-20 National Team, using his heel to flick the ball towards Isagi who was making a run, over the heads of the U-20 defense.
Controls: Even before Blue Lock, Nagi possessed exceptional control, able to catch a cell phone in mid-air while jumping down a flight of stairs. This feat alone was so impressive that Reo immediately recognized his footballing talent and decided to make him his partner. He can control with his entire body, with lethal effectiveness, constantly finding ways to turn a bad situation into something favorable. Nagi has controlled the ball with his toes, heels, and even his back, demonstrating the versatility of his control. He can control virtually any object and often uses his control to manipulate and confuse his opponents when running down the field, which combines with his spatial awareness to position himself in the best possible spot for surprising controls and follow-up shots. After training in the Neo-Egoist League, Nagi's controls have evolved, and he can control while being pressured by two defenders and control a high-powered close pass while moving at high speeds with ease.

Creative Control: When Nagi approaches the ball with a defender behind him, he can use his first touch to throw the ball over his shoulder and around it. Isagi described this as creative control, which brings a play to life.
Black Hole Control: Alternatively, if Nagi is not pressured by his opponent, he can use an Absorbing Control, catching the ball in mid-air and killing its momentum. This gives him the time and space to prepare his next move.
Controlled Shot: This is her most common ability and she uses it frequently in her matches. Nagi first performs a control with the ball, whether it is moving or not. From this point, she kills the speed and momentum of the ball so that she can manipulate it and perform a precise shot that breaks through the opposing team's defense and effortlessly scores a point.
Zero Reset Spin: While being pressured by multiple defenders, Nagi can hold them off while perfectly controlling an incoming ball and then instantly spin to push the ball away from the defenders and charge through them, restoring the flow of the game mid-match.
Juggler Shot: After controlling a ball while it is moving and giving it time in the air, Nagi can relax his body in mid-air, swing his legs around the ball and kick it with extreme force performing a monstrous volley shot.

Current state (incomplete): Current, as described by Ego, is the state of "total immersion" or "being in the zone." It is the mental state in which a person performing an activity is completely immersed in a feeling of energized concentration, total participation, and enjoyment in the process of the activity.
Nagi has entered the Stream state numerous times in Blue Lock, sometimes intentionally and sometimes unintentionally, but he has yet to master it. His most impressive feat in the Stream state was the fake volley shot.
Two-Stage Fake Volley Shot: First performed in the rematch between Isagi's White Team and Rin's Red Team, when Nagi was under pressure to score and prove himself on the field in such a high-stakes match. Nagi begins by preparing a powerful shot from an incoming pass, but at the last second, he changes the angle of the shot to make the ball spin in the air. The speed of the ball's spin causes it to hover in place, allowing Nagi to follow up with a high-powered shot. Even Rin couldn't predict or counter the move, and it was good enough to provoke him and get serious. When Anri first saw it, he described it as a miracle, but Ego suggested it was a move made possible by the current state.
Five-Shot Revolver Fake Volley: Nagi first perfectly catches a drop pass in front of him, giving it some time in the air, and then instantly positions himself in shooting form. He powerfully kicks the underside of the ball in mid-air, killing its forward momentum and giving it spin like his two-stage fake volley, but instead of shooting, he performs the fake volley again, giving the ball even more height in the air. Nagi performs a fake volley and juggles the ball in the air two more times to evade defenders.