Shun Kakei

The Poseidon's fourth-tallest player (202 cm) and de facto captain, Kakei is the first character to allude to the existence of a "real" Eyeshield 21 in the series. Shun attended middle school in the United States, where he witnessed the play of this true Eyeshield 21, a running back for Notre Dame University's affiliated middle school (later revealed to be Yamato Takeru). Amazed by the prowess of a Japanese player, Kakei became reinvigorated with American football after having been frustrated by his inferiority to the American players around him. When Kakei's team Arizonia University's affiliated middle school played against Notre Dame, Kakei and Eyeshield 21 played against each other on a single play, and while Kakei lost, Eyeshield 21 promised to play him again. Kakei trained hard, practicing how to use his great height to his advantage, and became the team's ace player. However, by the time Phoenix played Notre Dame the following year, Yamato had departed for Japan, and the Notre Dame players had been instructed not to speak of his existence but most of players along with the coach were really mad about not being able to speak about him because they respect him and were really mad at oberman for doing such a rotten thing. Kakei returned to Japan as well, determined to find Eyeshield 21 again, and joined the American football team at Kyoshin. Under Kakei's direction, the Poseidon adapted their belief that height was essential to winning American football, and the team recruited several more tall players. When he learned of the "fake" Eyeshield 21, Sena, playing for the Devil Bats, Kakei declared him an impostor, knowing the Eyeshield 21 he had encountered in America to be taller and stronger. Kakei despises Sena and believes him unworthy of his title before and then throughout the Kyoshin-Deimon match, and is determined to expose his inferiority. After being defeated at the end of the game by Sena's newest technique, the Devil Bat Hurricane, Kakei deems Sena worthy of the title Eyeshield 21, but warns Sena that the Eyeshield 21 he met in America will one day stand against him. Kakei becomes a friendly acquaintance of the Devil Bats, appearing at several of their games as a spectator. When he learns that Sena will play against Yamato, whom he believes and later confirms to be the true Eyeshield 21, Kakei vows to teach Juumonji all of his hand techniques in the hope that Juumonji will be able to help Sena defeat Yamato.

Kakei is physically distinguished by his great height, long powerful arms, and fierce blue eyes. While physically powerful, he has a slender build, and draws his strength from using his great height to gain leverage on his opponents. He is capable of holding back or even shoving to the ground most players shorter than himself with a single hand. His long arms also provide him with an extended reach, which allows him to counter against a runner's feints more effectively. Kakei is also a strong strategist, personally being able to discern how to defeat the Wishbone. He is named one of the best three linebackers at the end of the Fall Tournament.