As ahill said, Baba collects fighters from all over the afterlife, Hell included. For what video games are worth, this is further reinforced by Harukanaru Densetsu where she adds the CHADitz to her roster and brings him back for one day to fight Gohan as part of his training.
ahill1 said:
It's curious that Dabura is mentioned as the king of the demon realm or something like this... I wonder if Akkuman knew about Dabura or shivered at someone mentioning him.
Considering Hell and the Makai are in two completely different dimensions, probably not. It'd be the same as an Earthling casually knowing about Dabura, not to mention no souls in Hell would be aware of him as those killed by demons would be unable to transcend to either part of the afterlife.
The only kind of interaction we're given about them is if pitting them against each other in BT3, which doesn't give any indication that Akkuman knows more about Dabura than what Dabura tells him.
