Mr. Satan, also known as Hercule, is the World Martial Arts Champion and the Earth's protector in the Dragon Ball Z animation and video games. His real name is actually Mark. When Mark was young, he attended a fighting dojo called "Satan Castle." Through a combination of considerable power and good luck, he quickly became world champion and was called "Mr. Satan" after the name of his dojo. During the Dragon Ball X time period, Mr. Satan won the champion title by beating normal earthlings in a time when Goku and the other fighters were battling on Namek. He was already famous and rich, which resulted in him also being a egomaniac. On television he kept talking big about his strength and that he was the best fighter in the world.
Using his fame as "the Hero who defeated Cell", he seduces and sleeps with girls, acting like a leech who always turns his head when seeing a pretty face. He is very protective of his daughter Videl however, and would not allow her to hang out at any boy's house unless they are tougher than him.
If you dig deeper down in Mark's personality, he's actually a decent and honorable man with a kind heart. He genuinely cares about protecting the innocent and fighting for justice the best as he can. He shows moments of great courage when his family and friends are threatened by evil.
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