Goku

History
Goku was born on the Planet Vegeta alongside many other saiyans. They say he was very weak and only had a power level of 2. This is confirmed in the movie Broly The Legendary Super Saiyan.Goku's original name is Kakarot and had gained the name Goku from his Grandpa Gohan. Goku's father was Bardock a saiyan who worked for Frieza until he learned of Frieza's plans. Goku's mother was never seen nor heard of, so her identity is not known. Goku once found by Grandpa Gohan was trained to be a powerful warrior by Grandpa Gohan. He was not the normal type of human though because he was not human at all. He was a saiyan. Goku never knew this till he was grown up, but he did realise that he had a tail and could fly unlike most other people.

Saiyan Saga
The Saiyan Saga opens with the arrival of Goku's brother Raditz. The Z-Fighers are no match for Raditz and he escapes with Goku's son Gohan. Goku fights Raditz again alongside Piccolo ( the descendant of King Piccolo) and is killed when Piccolo can't get a shot on Raditz with his Special Beam Cannon leading Goku to hold Raditz down to one position and letting Piccolo hit both of them with the Special Beam Cannon. Raditz then tells Piccolo to be prepared for two more sayains to come way more powerful than Raditz himself. We see Goku's dead self on the way through King Yenma's office. King Yenma gives Goku clearence to go through Snake Way to get training with King Kai Goku races off. He gets there after hitting many obstacles and gets his training from King Kai and learns the Spirit Bomb and Kaioken. Goku is then wished back to life by his friends and races back to earth to help fight the new saiyan threats Vegeta and Nappa. When Goku gets there most of his friends have been killed and his son and Krillan ( a good childhood friend of Goku's) are left to fight Nappa. Goku destroys Nappa with the Kaioken and starts to fight Vegeta. Vegeta is a tough opponent for Goku, but Goku beats him and decides to let him live. Vegeta leaves and thus ends Goku's first adventure.

Frieza Saga
The beginning of the Frieza saga Goku was still on Earth recovering from the fight with Vegeta. Once he was fully recovered he got on a Capsule Corp. ship and flew to Planet Namek where he would be fighting Frieza. Once he landed on Namek he flew right towards where the action was with the Ginyu Force. Once he got there He fought a Ginyu Force member named Recoome and annihilated him in one hard punch to the gut. The next fight Goku faces is Burter, who is fast and powerful, but is no match for Goku. Goku Punches him in the face so Hard he killed him and left his body laying on the floor of Planet Namek.Goku's next challenger is none other than Captain Ginyu himself. This battle is tough, but yet Goku whips him at first. Goku saw victory at hand until Ginyu pulls out his secret weapon the Body Change. This leaves Goku with the weakened Ginyu body and Ginyu with Goku's still powerful body. Thanks to Vegeta and Goku's Friends Goku gets his body back, but is so weak they have to put him in a rehabilitation chamber. Goku is out for a while, but once he is back he goes and fights the evil Final Form Frieza. Frieza proves to be the most powerful opponent Goku had yet seen until Frieza angered Goku. Once angered Goku becomes a Super Saiyan and crushes Frieza. Frieza has been beaten and all Goku has to do is get back to earth, but you don't know what happens to him cause all you get to see is him rushing around Namek looking for a way off the dying planet and then the planet explodes. Thus ending another one of Goku's adventures.

Cell Saga
Cell saga was when Goku showed some more udates in his power. He used his new powers to get himself back home to planet Earth where he ran into a kid named Trunks from the future. Him and Trunks fought and Goku was given an antidote that was to stop him from dying form a fatal heart disease. He took the formula and prepared to fight another threat known as the Androids. Goku and his friends confronted the first two of them, but they were stronger than Goku expected. Through the fight with Android #19 Goku is hit by that heart disease and is uncapapble of fighting any longer. Goku is not seen again until he stops Tien from being killed by a new threat known as Cell. Goku then trains with his son in the Hyperbolic Time Chamber and gains the super saiyan leveled form and is stronger, but slower. Goku then fights Cell in which he stops and lets his son Gohan fight. Goku then is killed by Cell when he tries to stop Cell from blowing up the planet. This concludes Goku's role in the Cell Saga.