The final major antagonist that Goku and the Z Fighters encountered in Dragon Ball Z was the magical Majin Buu. A monster created by the powerful wizard Bibidi centuries ago, Majin Buu cut a path of destruction that wiped out scores of inhabited planets and killed millions before he was sealed away on Earth by the Supreme Kais.
And, in the MMO video game Dragon Ball Online, an entire race of playable characters and NPCs from the Majin race were introduced, all resembling the original Majin Buu that once terrorized the cosmos long ago.
Majin Buu was originally intended as a singular being, a malleable, pink creature that was virtually indestructible and possessed both great combat strength and a nigh unmatched regenerative ability. After absorbing two Supreme Kais, Buu took on a more corpulent, jolly appearance, with his inherently evil nature now tempered by childish innocence. Buu would manage to isolate his evil impulses into a completely separate being that was revealed as the villain's original form, known as Kid Buu, with the sentient evil resurrected as the good-hearted Uub after being destroyed by Goku's Super Spirit Bomb at the end of the DBZ.
Dragon Ball Online expanded on Buu's ability to spawn sentient beings from himself and his unusual abilities. Sometime after Goku left to train with Uub in the final moments of DBZ, Majin Buu gradually became more and more envious of the lives humans led, especially their ability to form loving relationships and build their own families. After finding one of Mister Satan's dirty novels, Majin Buu takes a portion of his own body to mold into the sentient female being named Buuby, designed after his own amorous desires. After Buuby came alive, Buu immersed her in a "Love Beam" (?!) that made his newly-created wife pregnant with Baby Buu, with the Majin race beginning to flourish from this union.
By the time of Dragon Ball Online's native time period in Age 1000, approximately 216 years after the conclusion of DBZ, the Majin race has become one of the major populations on Earth, alongside humanity and the Namekians after their planet New Namek was destroyed by the villainous Mira in Age 853. The Majin race, in particular, featured two visible subsets: The Wonder Majin took after the heavyset Majin Buu and are largely a support class, while the Mighty Majin took after Kid Buu, displaying the villain's vicious fighting techniques and abilities as players moved to defend Earth and the Dragon Ball timelines from Mira and Towa as they attempt to change history and invade from the Demon Realm.
With players training their characters in Dragon Ball's iconic martial arts techniques and growing stronger as they travel with Time Patrol Trunks across divergent timelines to keep reality safe, the Majin race is one of the mightiest allies the Time Patrol has. All from Majin Buu's fascination with humanity's capacity for romantic love and the ability to procreate, the magical monster showed new depths to his own abilities by crafting a wife for himself and using his powers to create a child.
And with the Majin blending both the more innocent and violent aspects of the character's history, Dragon Ball Online showed another interesting facet to the pink creature as his own drive to love helped save the world through his offspring.