Goku is the Strongest Saiyan of all time.  His rival is Vegeta.  He has a son named gohan.  Goku can fuse with Vegeta to become Vegeto.  He was the first to turn super saiyan 3 alone.  He defeated Buu.  Goku defeated Freeza, Cooler, and Broli.  He won the tournament when he died and defeat piccon to win the tournament.  He is also the father of Goten and is married to Chi-Chi.  He has betan almost everybody.  HE is the nicest's saiyan and always try to keep the peace.  He saves the world almost every time when it is trouble.  He did as a result of cell blowing up in the cell saga where Goku gave his life to save the world. Gran Kai gave his life up for Goku to come back to life to save the world from Majin Buu.  He had to use the Earings of fusion to fuse with vegeta to atempt to defeat Buu.  They were suppose to be stuck together forever but  they split up inside Buu's body.  That is the main story on Goku