Incedibly strong for his age (which he claims to be of 14 years, but later we find out that he can't count), he has one of the Dragonballs which he refers to as his Grandfather (it was the only thing that his Grandfather left him before dying, so he considers it to posses his soul). Goku while carrying his lunch home (a giant fish that he killed with one kick) literally bumps into Bulma. After a brief discussion, and Bulma explaning the power that lies in the Dragonball, both leave to search for the Dragonballs. It is in this way that the series of adventures begin. Soon after, both meet Master Roshi who then gives them his "first" majic cloud (which he frequently has destroyed, but later we find out there is a bunch of them), also known as Nimbus.
After some 17 mangas, Goku has had many adventures and makes new friends and is already an adult. He's married (with ChiChi) and has one son (Gohan, he was given the same name as his Grandfather). - On the TV series the name is changed to Dragonball Z - By this time, with the coming of Goku's brother: Raditz, we find out that Goku isn't human. He was found by his "Grandfather" (Son Gohan isn't his real grandfather, but an adoptive one) inside a space capsule; Goku had been sent to Earth in order to conquer it, but due to a hard fall he lost his memories, thus, becoming the innocent boy that we meet in the beginning of the manga; we are told that Goku is a Saiyan and that the Saiyans live on the planet Vegeta.
Later Goku finds out that he can turn into a Super Saiyan when he gets really angry (this occurs first time when Frieza, one of the most dangerous enemies in the series, kills his best friend Krillin, during his quest to find the Namekian Dragonballs). This transformation greatly increases Goku's power and gives him physical transformations (his hair becomes blond, longer and more spiky, his eyes green and his face linear and an aura forms around him); afterwards he finds that he can turn into Super Saiyan 2 and 3, which means an increase in all of the characteristics of the first stage. Later on Goku also becomes Super Saiyan 4 and his hair becomes black again and grows red hair on his body and has a tail that is red too (weird because Goku had his tail surgically removed when he was a child).
