Majin Buu is introduced in the Dragon Ball Z series during the final saga called the Buu Saga. Buu is a five million year old extraterrestrial monster who has been dormant on Earth for most of his life. Due to his extreme power and ruthless nature, the wizard Bibidi had him sealed away on Earth millions of years before Dragon Ball. Bibidi's son, the wizard Babidi, would search for Buu in an attempt to revive him and continue his father's work.
It is perhaps worth noticing, though it is not relevant to the story itself, that the names of the characters, Bibidi, Babidi and Buu (Boo) came from the song of that title from Disney's animated film Cinderella.
Before he was sealed away, Bibidi used Majin Buu to wage war against the supreme rulers of the Universe (Kaioshin). Due to Buu's extreme power, even the Kaioshin were defenseless against his attacks. During the final battle of the war, Buu absorbed the Dai Kaioshin (God of all Kaioshin). However the Dai Kaioshin, being so pure and kind, changed Buu's heart from ruthless to innocent. It also caused Majin Buu's power level to drop substantially. The last of the Kaioshin (the East) escaped and later killed Bibidi after Buu was sealed away.[2]
Kid Buu is the original demon created by Bibidi[3] and Uub is the pure good, reincarnated version of Kid Buu.[4]Buu's most effective and deadly power is his uncanny ability to regenerate from extremely high levels of damage, even if his body is almost completely destroyed. This ability gave him his greatest advantage over foes who were able to damage him but not completely eliminate his malleable body. Buu can regenerate lost limbs, repair physical damage and even pull his body together after being blown into several hundred pieces or even converted to dust. This ability makes Buu virtually invincible against opponents unable to destroy and disintegrate every last molecule of Buu's body through incredibly enormous energy attacks (presumably at a level substantially higher than Buu's). It should be noted that Cell had a very similar regeneration ability, though not nearly to the degree that Buu possessed.












