Raditz is the tertiary antagonist of the Saiyan Saga in Dragon Ball Z. He is the older brother of Goku and the first antagonist in Dragon Ball Z and Dragon Ball Z Kai. He is one of the last four surviving members of the Saiyan race, and comes to Earth in search of his brother, to see if he had taken over Earth, as he was supposed to. However, Goku hit his head as a child and lost all memory of his mission and who he was. Raditz is also the first Saiyan to come to Earth, and at that point he was much stronger than Goku, and Piccolo, who had teamed up to fight and defeat him.
Personality
Like all Saiyans, Raditz is brutal, prideful and sadistic. He loves to fight and he will gladly kill any member of his family if it means coming out on top. Despite being a heartless brute, Raditz is a manipulative coward in the face of death. To prevent being killed by Piccolo's Makankosappo, while Goku twists his tail in order to subdue him, Raditz "promises" to leave Earth and never come back. Because of his naivete, Goku releases him and he fights back.