Goku

This is the hero of DBZ. Goku is a Saiyan (3rd class fighter)
He was sent to earth before Freeza blew up Planet Vegeta, and was suppose to conquer it. Luckily, Goku hit his head and forgot to destroy Earth. Goku was adopted by Son Gohan. Goku  accidentally killed him when Goku transformed into a Giant Ozauru and stepped on him

Goku met Bulma at a young age and went on a quest with her to find all the Dragon balls. Goku trained under Kamesennin and became friends which Krillin, the other disciple of Kamesennin. Goku eventually became the strongest man on Earth and defeated the great Piccolo. later on he became the first Saiyan on the show to become a super Saiyan. Goku killed Freeza and became the strongest being in the universe.

GOku is married to Chi Chi, and has two sons. Gohan is his first son, and Goten is his second son. Goku is a warm hearted guy, but he is not too smart. He won only 1 Tenkaichi Budoukai Tournament, but is still the best warrior in the world.