Doctor Ivo Robotnik, also known as Dr. Eggman, is Sonic the Hedgehog's arch-nemesis and the main antagonist of the Sonic the Hedgehog series.He is an obese mad scientist with an IQ of 300 and an egg-shaped body.His greatest goal was to turn the animals of Mobius into his robotic slaves and dominate the world from which he would rule his empire, Eggman Empire.He has launched various schemes involving acquiring the Chaos Emeralds or tapping into something else usable as a weapon. Despite his best efforts, Sonic and his friends stopped him over and over. Eggman plays an important part in Super Mario Bros. Z, albeit a small one. He had created Metal Sonic and a large space station called the Death Egg .However after the robot rebelled and merged with some Sonic robots, it persumably killed him and sent the space station to crash at Mobius causing the planet to have a dark atmosphere.Although not confirmed as of yet, it is obvious that he is the mysterious doctor that Bowser talked to in Episode 7. It is revealed here that he has invented Bowser's doomship, (possibly) several advanced starfighter ships, and a new robot doppelganger, Mecha Mario.He appeared in Episode 7 and Episode 8 . Since this is still unconfirmed, it could be possible that he could be really Eggman Nega (An interdimensional/future counterpart to Eggman), but the "Eggman" that is seen has round glasses instead of oval glasses, meaning that he really could be Dr. Eggman (Eggman Nega has, however, been known to disguise himself as the original Eggman, so this does not break the theory completely). His current terms with Sonic are still unknown, nor is it certain that he was aware of his presence in the first place. For currently unexplained reasons, he was still in shadow in Episode 8 despite being in a clearly lit room. This may be an attempt to keep the character or a mystery, or an implication that Mecha Sonic may have charred his skin during his rebellion.
Like most villains, Dr. Eggman is defined by his ego. His idea of a perfect empire involves his image plastered everywhere and even his former fortress, the Death Egg, has his face on it. He generally considers himself a genius without peer, save possibly his grandfather, Gerald Robotnik. When his plans break down, though, he loses his temper rather easily and can have some childish behavior.
Despite his evil ways, Eggman has been shown to fight against a greater evil when his own life or that of Mobius is threatened. His reasoning is mainly that he can't exactly conquer the world if there's no world left to conquer.
Eggman, though somewhat tougher than he looks, is not a very physical fighter. He can move surprisingly fast when fleeing, but doesn't possess notable strength or speed in combat. He can take a few hits, however, and is good at fighting with his technology.
Eggman's greatest skill is when he's in the cockpit of one of his robots. He has been shown to be an ace pilot and highly skilled in controlling his creations, making him much more dangerous.
Dr. Eggman seems to know Mario as well since he appeared in the Mushroom World. However, he wants to destroy Mario by the fact he created Mecha Mario, just like he created Silver Sonic, Silver Sonic II, Metal Sonic, and Archie Mecha Sonic (Despite being the roboticised version of Sonic in the Archie Sonic comics) to destroy Sonic.
Mario is reminding Dr. Eggman's troublesome memories of Sonic persuing him, however, Mario expects to battle Bowser.