Bowser

Bowser is the overgrown king of the koopas and Mario's #1 archenemy. Bowser debuted in Super Mario Bros, as the final boss. He has appeared in almost every single Mario game, with the exeption of Donkey Kong, Donkey Kong Jr, Super Mario Land, and Super Mario Land 2: 6 golden coins. In most games, Mario fights him because he kidnapped Peach.