Mr. Satan--or Hercule in the TV broadcast of the English dub of the Dragon Ball Z anime--is the reigning World Martial Arts Champion.
Despite being strong for a human his power pales in comparison to Goku and his friends. He has an enormous ego and has stolen credit for saving the world on several occasions.
In the English dub version of the Dragon Ball Z anime by Funimation Mr. Satan was voiced by Chris Rager. Chris Rager reprises the role in the anime films, the video games and the sequel anime series Dragon Ball GT.
In the Ocean Group version of the Dragon Ball Z anime Mr. Satan was voiced by Don Brown.
In the Blue Water dub of Dragon Ball GT for European and Canadian broadcasts Mr. Satan was voiced by Dave Pettitt.
In the AB Groupe dub of Dragon Ball Z: Bojack Unbound, produced for European markets, Mr. Satan was voiced by Paul Bandey.