Radtiz came to earth to see if Kakarot had destoryed the life forms on earth, but when he saw the farmer he knew that Kakarot had failed. So he went looking for him, he ran into Piccolo and when he was about to kill him when his scouter showed a higher power level and he knew it had to be Kakarot. When he got there Goku had no idea who he was. Radtiz told Goku that his real name was Kakarot and that he was his older brother. Goku didn't want to kill everyone but radtiz took his son and made sure that Kakarot would carry out his mission. When he saw that Kakarot didn't want to carry out his mission he was forced to fight him. Radtiz doing very well until Goku grabbed his tail and made him very weak but since Goku was too trusting he let go then Gohan attacked Radtiz when he was beating up on his dad, then it was Goku who helped his son and gave up his life to save the earth. Piccolo used his Special Beam Cannon and killed both Radtiz amd Goku but before he died he sent a message to his fellow Saiyans about the Dragonballs on earth. Then he died.
