Good Buu (魔人ブウ：善; Majin Bū Good), also known mainly as Majin Buu is the result of the Innocent Buu using fission to split into good and evil halves. He would go on to become a member of the Z Fighters and live with Mr. Satan. After the battle against the pure Majin Buu, Buu is referred to as Buu instead of Majin Buu and to the world he becomes Mr. Buu.
Majin Buu has many forms, all of which are linked below. However, each form has a different personality and goals, essentially making them separate individuals. All of Majin Buu's forms are simply referred to as "Majin Buu" in the series, but the various forms get their common names from various Dragon Ball Z video games.