Born from Anger, Another Majin!
Just as a peaceful life seems within reach for Majin Buu and his new companion, a sudden act of senseless violence from malicious onlookers shatters the calm. Pushed beyond the brink of emotional control by the senseless attack, Buu's internal turmoil reaches a critical boiling point. As his overwhelming fury erupts, a terrifying transformation begins to take shape, threatening to unleash an even greater evil upon the world.
Aired 14/12/2014EP 36 - Born from Anger, Another Majin!
Dragon Ball Z Kai: The Final Chapters
Since Cell's defeat Gohan has grown up and go to the university then she meets Videl which who has some adventures, then both and his new brother Goten are training for the new tournament, in which Goku came back from the dead for one day. In half of the tournament a misterious persons advice the group about the resurrection of the dangerous Majin Boo, but all plans fails and every one try new ways to stop The dangerous Majin Boo who gets stronger each time. Goku and his friends make everything for stopping them through fights.
(Source: Anime News Network, edited)
Note: Remastered version of the Majin Boo arc that adheres more to the manga's story.