Dr. Ivo "Eggman" Robotnik is Sonic's arch-nemesis. This large scientist with an IQ of 300 dreams of conquering Mobius, the world ruled by him and his robot army. Unfortunately for him, Eggman's constant plots to create his Eggman Empire are always thwarted by Sonic and his friends, who save Mobius from the environment destroying plots that the doctor comes up with.