Uub

Uub (ウーブ) is a supporting protagonist. He is the Human reincarnation of the evil side of Majin Buu and is one of Goku's students. Due to being the positive reincarnation of the completely evil Buu, his name is a result of reversing "Buu". Pawa says Uub is destined to be Universe 7.2's Emperor, as there hadn't been an Emperor since Goku killed the former one: '''Frieza. And so, at the end of the first season of the After Series, Uub becomes the Emperor. '''As the reincarnation of Kid Buu, who fought evenly against and ultimately outlasted Super Saiyan 3 Goku without any signs of fatigue, Uub is considered the strongest human character in the series.

Majuub
There was a time Uub fused with Majin Buu, the good side of Buu, in order to defeat Baby (now known as Projecto), This Fusion made him very strong. But in the Revenge Saga Evil Buu escaped thanks to Projecto and fought Uub along with Projecto. Uub was powerless and got absorbed by Buu, turning him into the compl ete Super Buu again.