Uub

Uub is the human reincarnation of Kid Buu, born as a result of Goku's wish at the end of the Buu saga that the pure evil of Majin Buu be reborn as a good person. He grew up in a poor village and was originally meek and nervous. Goku discovered him at the World Tournament and chose him as his final student, recognizing Uub's extraordinary hidden power. In Dragon Ball GT, Uub merges with the Good Buu to form Majuub, significantly amplifying his abilities.