Buu Saga Rulebook
Seven years after the Cell Games, Goku is allowed to go back to Earth for one day to reunite with his loved ones and meet his youngest son, Goten, at the World Martial Arts Tournament.
Soon after, Goku and his allies are drawn into a fight by the Supreme Kai against a magical being named Majin Buu summoned by the evil wizard Babidi. All efforts of preventing the resurrection prove to be futile as Buu is successfully revived, resulting in Vegeta, who had willingly joined forces with Babidi so he could surpass Goku, committing suicide in a failed attempt to kill Buu.
Goten and Trunks are taught the fusion technique by Goku, while Gohan is trained by the Supreme Kai to unlock his latent potential. Meanwhile, Buu befriends Mr. Satan and vows to never kill anyone ever again, but is interrupted when a deranged gunman shoots and nearly kills Mr. Satan. As a result, Majin Buu becomes so angry that he expels the evil within himself, creating an evil Buu that proceeds to absorb the good Buu. The result is Super Buu, a psychopathic monster who wants nothing more than the destruction of the universe.
After numerous battles that result in the deaths of many of Goku's allies as well as the destruction of Earth, Goku defeats Kid Buu with a Spirit Bomb attack containing the energy of all the inhabitants of Earth, who were resurrected along with the planet by the Namekian Dragon Balls. Goku makes a wish for Kid Buu to be reincarnated as a good person and, ten years later at another World Martial Arts Tournament, he meets Kid Buu's human reincarnation, Uub. Leaving the match between them unfinished, Goku departs with Uub so he can train him to become Earth's new defender.