Mephisto's a demon who rules a fiery kingdom called 'Hell' in his own words. After the downfall of Zeus and Hades abandoning The Underworld, Mephisto took over and now rules it. He's willing to do deals and trades, but for a price - usually one that's costly, cursed, and enigmatic. His deals can be a mixed bag, whether they're beneficial or harmful, but they're rarely what they seem like on the surface. They could have hidden costs or unexpected rewards. Mephisto also has a son named Blackheart.