Raditz is Goku's older brother. He came to Earth to see whether Goku had completed his mission of conquering the planet. Angry and intolerant, Raditz can't understand why it has taken his brother so long to destroy the helpless humans. When Raditz learns Goku had lost his Saiyan "programming" as a child and was now Earth's defender, he kidnaps Gohan with the threat of killing him if Goku doesn't bring him dead humans.

Goku and Piccolo go after Raditz and successfully pin him once. But ruthless like all Saiyans, Raditz plays on Goku's emotions and lies to his confused brother to avoid being destroyed. The minute he is saved however, he instantly turns on Goku.