After five years of peace, an evil menace comes to the Earth. It is Goku's elder brother, an extraterrestrial Saiyan, named Raditz. After Goku and Piccolo kill him, Bulma takes the from Raditz and fixes it to find the power levels of people in human numbers. During the subsequent battle against Vegeta and Nappa, Yamcha, Tenshinhan, Chaozu and Piccolo are killed and because Piccolo dies, the Dragon Balls are rendered useless.Dragon Ball Z manga, volume 3
