Ikki Niko is a 15-year-old male born February 5th (Aquarius) in Karuizawa, Nagano Prefecture. He stands 173 cm tall, weighs approximately 64 kg, has blood type O, and wears size 26 cm shoes. His short black hair deliberately shields his eyes and forehead, features he considers sensitive. Niko possesses a lean, average build not immediately suggesting athleticism. An early Yu-Gi-Oh! obsession led Niko to win official tournaments. When bullies from his school's soccer club destroyed his favorite card, he challenged them to a match 100 days later. Despite no prior soccer experience, he recruited top players from other clubs, studied tactics intensely, and led his team to a decisive 13–0 victory. This feat earned him a spot on the school soccer club, which he guided to national tournaments, catching Jinpachi Ego's attention for Blue Lock. Personally reserved and introverted, Niko speaks politely yet confidently. He avoids social interactions, preferring solitude for activities like binge-watching every season's anime premieres, favoring titles such as *Puella Magi Madoka Magica*, *BANANA FISH*, and *Chernobyl*. He listens to "only my railgun" before matches and collects Yu-Gi-Oh! cards. Niko dislikes grapefruit and swimming to prevent exposing his face. His cautious nature avoids unwinnable confrontations. In Blue Lock's First Selection, Niko acted as Team Y's hidden playmaker, directing strategy while teammate Hibiki Okawa initially scored goals. During Team Y's match against Team Z, Yoichi Isagi identified Niko's spatial awareness as the team's core weapon. After Isagi intercepted a critical pass, scored, and defeated Team Y, Niko wept but adapted, adopting a more aggressive, goal-oriented approach. This evolution elevated his Blue Lock ranking from 255th to 63rd, securing his advancement to the Second Selection with four goals. For the Second Selection, Niko teamed with Zantetsu Tsurugi and Reiji Hiiragi. Their data-driven tactics initially succeeded against Seishirō Nagi, Shōei Barō, and Hyōma Chigiri, but they ultimately lost when opponents adapted unpredictably. Niko concluded Blue Lock required transcending pure data reliance. He progressed alongside new teammates. During the Third Selection, Niko joined Team B under Tabito Karasu and Eita Otoya. He transitioned to center-back for the U-20 Japan match, using his spatial awareness to intercept passes from Sae Itoshi and block Ryūsei Shidō. Ego Jinpachi praised his "watchtower" ability to read threats and organize defense. Niko injured his ankle but declared a newfound enjoyment in "crushing forwards," signaling evolution beyond a striker role. In the Neo-Egoist League, Niko joined Italian club Ubers as a defensive midfielder, drawn by coach Snuffy's tactical systems. Against Spain, his performance secured a 23.5 million yen contract offer. Facing Germany, he demonstrated incomplete "Metavision"—constantly scanning the field without full head rotation—which enabled near-interceptions of Isagi but left blind spots exploited by Jingo Raichi. His contract value rose to 30 million yen, then 40 million after the England match. Niko's abilities center on elite spatial awareness and tactical intelligence. His "watchtower" style prioritizes identifying off-ball threats and intercepting passes over physical duels. This skill rivals Isagi's spatial perception, though his Metavision remains underdeveloped. He also organizes defensive structures and initiates counterattacks. Key relationships include a rivalry with Yoichi Isagi, whom he credits for inspiring his evolution after their first match. Niko respects Isagi's spatial awareness but aims to surpass him. He collaborated tactically with Zantetsu Tsurugi during selections and learned under Snuffy in the Neo-Egoist League. Trivia includes his favorite soccer player Luka Modrić, motto "The eyes are the window to the soul," and hypothetical purchases like a gold Yu-Gi-Oh! Blue-Eyes White Dragon card with 100 million yen. He washes his forehead first and last in baths and would shave his head on Earth's last day for a "refreshed" feeling.