I.M. Meen is an arrogant, insufferable braggart who believes he is the "most powerful magician in the world", even though he gets defeated by kids armed with only good grammar. Meen's arrogance is further illustrated in his terribly written self-insert stories, wherein he portrays himself as an amazing hero loved by everyone.
He is sadistic, self-absorbed, and (as his name implies) mean, he is constantly taunting the player character throughout the game and enjoys seeing them suffer.