Goku is the hero of Dragon Ball Z, the most powerful warrior on Earth. 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 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, and 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.

Vegeta is a powerful Saiyan prince. He and his comrade Nappa are two of the last surviving Saiyans. They come to Earth to destroy all life and sell the planet. Though physically small, Vegeta can power up to unbelievable levels. Ambitious and determined, Vegeta wants the Dragon Balls to gain immortality.