Unfortunately, I'm not exactly an "expert" when it comes to DBH, but I've got my fair share of knowledge on it. Bluetrekking, Zenkaibattery1 and SSJRyu1 probably beat me in just pure knowledge of the series and it's lore.
Blue and I were planning to make a blog containing a tier list for the game, and have it feature sections for characters from the game who aren’t notable enough to get their own profiles (Guys like Dark Broly). Wanna help us with that?
"Those are the Charismas. They are kinda a gag but it is shown that Chamel and other Demon Gods are their avatars. They also “created” the DBH world like a programmer would a game and they view the DBH world as a game but it is unknown if it is in a transcendent way or metafictional."
These guys being the strongest characters, according to Blue.
But yeah Prime Mechikabura is definitely the strongest of the original characters.
Blue also found explicit evidence that the Demon Realm is outside of time, so that's fun.