DBZ

As a boy at the age of ten, Ub is the first time in the martial arts world 28 tournaments, taking place ten years after the defeat of Kid Buu, want the prize money to help his family. Goku reveals that Uub here is actually the reincarnation of the human form Kid Buu, who was born of desire to get shortly before Goku beats Buu with the Spirit Bomb Super. And "trained by Goku and becomes a warrior in the Fighters Z, by helping to fight the enemies in the Dragon Ball GT.
Ub has good intentions to enter the world tournament, his plan is just groping to win the prize money of 10,000,000 Zeni to feed his poor village is starving. Be the strongest of his village, Ub then realizes that there may be people in the world who are still stronger than him. With this, Ub lose hope, and became even more nervous when insulted by Nok.
After the draw, which was modified by the application of Goku Majin Buu, Uub is set to challenge Goku in the first round, but is also nervous and back off when Goku stepped toward him. During the fight with Goku, he regains his confidence and power, after Goku causes deliberately insulting his parents. Ub increases the power at some point be able to hurt Goku, Goku out during the fight does not go Super Saiyan. After the game, and Goku Uub, Goku apologizes, then offers to train Uub. During the first Ub is concerned about the prize money, but Goku said that Mr. Satan will give all the money they need Ub. The two then go to the village of Ub train, which is the final scene of Dragon Ball Z.
Although the Fighters Z and other participants in the tournament Ub initially perceived as weak and inexperienced, the more he would have fought against Goku in his statement provoked and angry, the more apt to attack Goku and gain power. It is strongly suggested that by the end of their struggle, the power was equivalent to Ub Goku, who had not only bought the transformation the most powerful Saiyan before you jump in ten years, but had spent the last decade before the formation tournament. In addition, former timid boy was capable of producing powerful waves of ki invisible stone first time could raise the arena, and it was his attack signature by his punches and kicks basic.