History of Dragonball Z
Dragonball started when a mysterious boy named Kakarot was sent to earth and discovered. He was trained and renamed Gokou by his adopted grandfather and joined Bulma to get the seven dragonballs. He was later trained by Muten Roshi (Master Roshi) and met Krillen. Gokou defeated Pilaf, Piccolo The Demon King, Red Ribbon Army, and Piccolo Jr. Gokou got married and at a reunion at Master Roshi's place, Gokou met his brother Raditz. Raditz kidnapped Gohan (Gokou's son) and Gokou joined up with Piccolo to defeat Raditz. With the help of Gohan's Hidden power, Gokou sacrificed himself to let Piccolo deliver Mankasapo to Raditz. Piccolo told Raditz that Gokou would be restored to life with the dragonballs and Raditz said that the was two stronger saiyans coming to earth in a year. Gokou and Raditz died and Kame-sama asked King Yamma if Gokou could train with King Kai (Kaio-sama). Gokou traveled through the snake way and after six months, he got to King Kai's planet to train. Gokou learned various attacks like Spirit Bomb(Genki Dama) and Kaio Ken, in addition to increasing his speed and abilities. But he wasn't the only one training. Piccolo and Gohan trained together to the max and Krillen, Tenshinhan, Chaiotzu, Yamcha, and Yajirobe trained with Kame. The fight against the Saiyans was earlier than they thought and Yamcha was first to die in the hands of a Saibaman. Krillen tried to destroy the enemies but the saiyans Nappa and Vegeta didn't die. Then Chaiotzu self-destructed himself to kill Nappa but his death was in vain since Nappa wasn't hurt. Tenshinhan did a tai ko ho dan and used up all of his leftover energy, so he died. Piccolo sacrificed himself to save Gohan and he got blasted off to the next dimension. After a few minutes, Gokou got to the battlescene and killed Nappa. And after a long battle against Vegeta, Gokou and Friends were declared the victors.