Son Goku. born Kakarot , is a Saiyan raised on Earth and the overall main protagonist of the Dragon Ball series. Originally sent to Earth as an infant, Kakarot would be adopted by Grandpa Gohan who named him Son Goku. A head injury at an early age alters Goku's memory, ridding him of his initial destructive nature and allowing him to grow up to become one of Earth's greatest defenders. He constantly strives and trains to be the greatest warrior possible, which has kept the Earth and the universe safe from destruction many times.