If you are a Dragon Ball z fan at all then you will know Goku but for those who don't.
Son Goku (孫 悟空, Son Gokū), born Kakarrot (カカロット,Kakarotto), is the main protagonist of the Dragon Ballmetaseries created by Akira Toriyama. He is the adoptive grandson of Grandpa Gohan, the son of Bardock and Gine, the younger brother of Raditz, the husband of Chi-Chi, the father of Gohan and Goten, the grandfather of Pan, and later the ancestor of Goku Jr. Cheerful, tenacious and also a bit naive, Goku is a Saiyan originally sent to Earth as an infant with the mission to destroy it. However, an accident alters his memory, causing him to grow up pure-hearted and later become Earth's greatest defender, as well as the informal leader of the Z Fighters. Throughout his life, he trains hard and strives to be the greatest warrior possible and constantly strives to fight stronger opponents which has kept the Earth and the Universe as a whole safe from destruction many times.