Incredibly strong for his age (which he claims to be of 14 years but later we find out that he canīt count), he has one of the Dragonballs which he refers to as his Grandfather (it was the only thing that his Grandfather left before dying, so he considers it to posses his soul). Gokuu while carrying his lunch home (a giant fish that he killed with one kick) literally bumps into Bulma. After a brief discussion, and Bulma explaining the power that lies in the Dragonball, both leave to search for the Dragonball. It is in this way that the series of adventures begin. Soon after, both meet Kamessenin who then gives him his "first" magic cloud ( he frequently has it destroyed, but later we find out there's a bunch of them), also known as Kintoen.
After some 17 mangas, Gokuu has had many adventures and friends and is already an adult, married (with ChiChi) and has a child (Songohan, he was given the same name as Gokuu's Grandfather). - On the TV series the name is changed to Dragonball Z- . By this time, with the coming of Gokuu's brother: Raditz, we find out that Gokuu isn't human. He was found by his "Grandfather"(SonGohan isnīt his real grandfather, but an adoptive one) inside a space capsule; Gokuu had been sent to Earth in order to conquer it, but due to a big fall he lost his memory thus, becoming the innocent boy that we meet at the beginning of the manga; we are told that Gokuu is really a Saiya-jín (-jin is used in Japanese to say that a person is part of the people that the "-jin" follows, therefore, Gokuu is part of the Saiya people; living the Saiya in planet Vejiita (they are not originally from this planet-this we find out in one of the films).
Later Gokuu finds out that he can turn into Super Saiya-jin when he gets really angry (this occurs the first time when Freeza, one of the most dangerous enemies during the series, kills Kulilin, during the quest for the Namekian Balls). This transformation increases greatly Gokuu's power and gives him physical transformations (his hair becomes blond and more spiky, his eyes green, his face linear and an aura forms around him); afterwards, he finds that he can also turn into Super saiya-jin 2 and 3, which means an increase of all the caracteristics of the first stage.
Note: Songokuu is inspired in the monkey god of the Shinto religion (SonGokuu really looked like a monkey in the first Toriyama sketchs for Dragonball) .
Son Goku is the primary hero of the Dragon Ball series. The series started out with Goku as a child of age 12. Once he grew up and his son was born, the TV series' name changed from Dragonball to Dragonball Z. At the end of the series, Goku was roughly 45 years old. Goku is a Saiyan whose native world is the planet Vegita. He was sent to Earth in a space capsule right after he was born so he could conquer the planet. However, he hit his head and lost his "programming," thus becoming the kinder, gentler Goku we see in the series. Goku was raised as a human on Earth, and did not learn of his true nature until his brother Raditz came to Earth... Later, when Goku's rage was awakened by witnessing the death of his friend Kirilin, his Super Saiyan power was awakened. When he goes Super-Saiyan his eyes turn green and his hair gold. Currently, Goku can go to the 3rd stage of Super-Saiyan power.