Goku is the hero of DragonBall Z, the most powerful warrior on Earth and the first to become Super Saiyan in over 1000 years. When the Saiyans arrive, Goku learns the mysterious secret of his own past: He is a Saiyan formerly named Kakarot. Goku was sent to Earth as a baby to grow up and destroy the planet, but a head injury as a child scrambled Goku's programming. Instead of growing up to become a destructive super-warrior, he became innocent and pure of heart, fighting for good.
Goku is peaceful, good natured, honest, loving to his family and friends, loyal, trustworthy, brave. If he has a weakness, it is his trusting nature. He always finds the "good" in people when others don't see it, though Goku's enemies sometimes take advantage of his naive trust.
He originally trained under Master Roshi and wears his symbol until he trains under King Kai. Then he wears King Kai's symbol. Goku grow up and marries Chi-Chi. Together they have two sons: Gohan and Goten.