He is a master fusion, and was fused in order to stop the Ultimate Absorption Warrior, Hiro-Buu. Who is Buu, who absorbs Cell. And then later absorbs Hirudegarn. He has very random personalities. At one moment he will act like Vegeta or Goku, or Vegito. Same way again with Goten or Trunks or Gotenks, or sometimes he just acts like Gohan. He thinks if funny how Bulma, Chi-Chi, Videl and Valese are fighting over who he belongs to, but when he laughs they always either shoot at him, or hit him with a frying pan, and once he was even hit with a book because they broke into a fight while he was reading a ton of books.