An archnemesis? I'd say mine would have to be someone with a charisma almost like that of a cult leader who draws followers with false promises of happiness. He would have command over other people like a dictator with an iron fist yet somehow they'd obey him happily, calling my suggestions that they are brainwashed "stupid" or something juvenile like that. And this archnemesis would have to do better at me in school as well, albeit with more cheating on tests and assignments.
Too long; didn't read: I have a problem with cult of personalities. Anyone with one is a good candidate for my enemy.