Son Gohan is the old man who adopted baby Goku. His name means rice. He taught young Goku fighting moves such as Jan Ken (rock, paper, scissors, the game is called Jan Ken Po) and gave him an extending stick called Nyoibou (aka Power Pole). He is a kind old man and was also trained by Muten Roshi. They lived in the woods and he let Goku sleep on his thigh. Son Gohan appeared in Dragon Ball, and died before the main story began. Goku saw the full moon and turned into an Oozaru where he lost control and killed his grandpa. He was left with the 4 star Dragon Ball which he thought had Son Gohan's spirit inside. Grandpa Gohan came back to life for a while to see how Goku was doing, and wasn't angry at him. Goku named his first son after his grandfather and Goku and his descendants inherited Son Gohan's surname.