Sena Kobayakawa a.k.a. Eyeshield 21 , is the main character.
Initially a bullied gopher, his speed was discovered by Hiruma as he was literally forced into joining the football team at Deimon. While insecure and clumsy at heart, Sena matures over the course of the series as he soon grows to love the game he plays and becomes an accomplished football player through his own strength and the guidance of his friends and rivals.

Source:Wikiepdia