Where do these DBH characters appear as Demigra?

[SIAD]

They tend to talk a lot about characters like Demigra, Goku (Xeno), etc. And that they are on the Multiverse + Level. I have seen the 26 chapters of the DBH Anime, but I have not even heard of Demigra.

DBH is a Manga?

 

[Captain Cadaver]

Demigra debuted in the game DB Xenoverse. His performance in the game isn't too impressive for his base self compared to the others, being outmatched by 70% BoG Beerus. Once he achieves his Demon God form by absorbing Tokitoki though, is when he gets catapulted to Multiverse+ level. He states he has control of all time and space across the multiverse (of which in the video games we know to have an infinite number of alternate timelines and made it very clear he would destroy all alternate histories to create his own.
His self from the DBH video games scales to the same level of power from similar feats as he planned to do the same thing to not just the DBH multiverse, but the real world as well. Xeno Goku and anyone on his level scale from this as Goku beat him in base.