Gohan is the son of Goku and Chi Chi. Gohan is 1/2 Saiya-jin 1/2 Human. After seeing what Gohan did to Raditz, Piccolo realizes that Gohan has the potential to become the most powerful person on Earth. Gohan trains with Piccolo to prepare against the Saiya-jins. Gohan is a little kid and gets scared to kill Nappa when he has the chance. Gohan helps Goku, Kuririn, and Yajirobi defeat Vegeta.
Gohan also fights alot of battles on Namek, and even brings down the tyrant Freezer for a minute.
Gohan becomes a Super Saiya-jin in the Room Of Spirit And Time with help from his father Goku. Gohan goes Super Saiya-jin 2 in the Cell Games and kills Perfect Cell. Gohan is only 10 or 11 at the time. However, Mr. Satan takes all the credit for killing Cell.
7 years pass and Gohan goes to high school. Gohan becomes a crime fighter called the Great Saiyaman, but his identity is eventually discovered by Videl, Mr. Satan's daughter. Gohan teaches Videl how to fly if she keeps a secret. Gohan also teaches his little brother Goten to fly. Gohan learns special training from DaiKaioshin, and Gohan reaches Mystic Form. But Gohan doesn't win against the evil Buu. Gohan's full potential is never released, due to his mother constantly making him study as a child, and because he doesn't thirst for battle like full-blooded Saiya-jins. Gohan eventually marries Videl, and they have a daughter named Pan.