Doctor Eggman

In an alternate universe, Robotnik succeeded in crushing the Freedom Fighters along with the royal family, essentially conquering Mobius. However, rather than kill Sonic and his cohorts once he captured them, Robotnik transformed each into cyborgs with half robotic/half organic bodies; this proved to be a mistake once the cyborg Freedom Fighters retained their self-awareness and mounted an assault on Robotropolis. In a desperate move, Robotnik used his own Roboticizer on himself, becoming Robo-Robotnik.

After that, Robo-Robotnik sought after a legendary giant robot called the Giant Borg. With the help of Scourge the Hedgehog (aka "Evil Sonic"), he succeeds in discovering it. Robo-Robotnik piloted the Borg by himself, wreaking havoc until he was struck down by the force of thousands of alternate Sonics, each arriving from their own reality to pummel the Borg to pieces. The scattering of Robo-Robotnik's weapon seemingly destroys him, reducing him to a severed head. Unbeknownst to anyone, he survived by transferring his brain to an empty space station in orbit, where he remains in a stasis.

Meanwhile, the Dr. Robotnik of Mobius Prime was vaporized by E.V.E., a machine that was designed to kill Sonic, but ended up attacking Robotnik instead. Rather than dying, Robotnik is actually sent to the alternate reality of Robo-Robotnik, where he meets his robot self. Robo-Robotnik appears on a monitor and explains that the station itself is still incomplete, keeping him mired in space until his systems run down. After assisting Robotnik Prime in returning home, he later follows him to Mobius Prime. After conspiring from the shadows for several issues, Robo-Robotnik, wearing a skin disguise to fool everyone into thinking he was Robotnik back from the dead, eventually lures Sonic and the Freedom Fighters to his orbital platform in space. A brief battle with Sonic ends with Robotnik being doused with acid, removing his disguise.

The Freedom Fighters enlist the help of Snively to blow up the orbital platform with Robo-Robotnik in it. His body destroyed, Robotnik retreats into a new robot shell back on Mobius. With his new body he takes on a new name: Eggman. While in this form, he also briefly has the power to roboticize anyone by touch, similar to the Midas Touch. If the victim is unwilling to be roboticized, however, they are rendered little more than a metallic statue instead, a fate shared by Nate Morgan and others.

Eggman continues to lose his body numerous times, only to download himself into a new robot shell. He later finds himself, Snively (who had by this point been roboticized), Sonic, and Tails captured by an alien race known as the Bem. Eggman and Snively are transformed back into flesh and blood, and forced to battle for their lives against a roboticized Sonic and Tails in order to prove whether or not flesh is superior to metal. Eggman and Snively are later re-deposited on Mobius without being changed back, and have remained that way ever since, unable to re-roboticize themselves (due to an after-effect of the Bem's deroboticizer).

Not long after this, Mobius is attacked by another alien race: The Xorda. After Sonic is accidentally lost in outer space, Eggman takes advantage of his absence by creating the "Eggman Empire." He strikes a deal with the Dingoes, providing weapons and other support for them, in return for their allegiance and becoming his enforcers on Angel Island. With the Dingoes now an ally, he successfully conquered the Floating Island and maintains control of it to date. His robot legions were controlled by a sentient computer named A.D.A.M. (short for Autonomous Digital Assault Microbe), prior to A.D.A.M.'s betraying his 'father' and subsequent destruction. Eggman also changes his main base of operations from the nuclear wasteland of Robotropolis (after being tricked into lowering the shields, nuclear missiles infiltrated the city and irradiated the area) to New Megalopolis.

Most recently, he has launched a large-scale offensive against the Kingdom of Acorn, using his Egg Fleet to inflict heavy damage via aerial bombardment, and taking nearly the entire population prisoner with the intention of using them to power his operations via his Egg Grape Chamber. He also engaged in a one-on-one duel versus Sonic wearing a fearsome suit of power armor, thrashing the hedgehog physically and psychologically before departing, though would come to regret leaving Sonic free when the Hedgehog and a handful of other survivors launched a rescue mission that foiled his plans and liberated the prisoners, though appears intent on rectifying this, deploying his egg fleet to the newly-revealed New Mobotropolis to try again. When he arived, he had Snivley and the Egg Fleet open fire on New Mobotropolis' shield. Sonic, the Freedom Fighters, and the Chaotix fought and defeated Eggman, sending him back to his base. He was most recently seen forging an alliance with the Dark Legion, reinstating Dimitri as Grand Master over Lien-Da, whom had assumed control in his absence.