Dr. Ivo "Eggman" Robotnik

Dr. "Eggman" Robotnik (aka Robo-Robotnik, Robotnik Mack II) is a version of Dr. Ivo Robotnik from another dimension. He first came face to face with Sonic the Hedgehog in the Mobius Prime reality when he was attempting to assemble the Giant Borg battle machine. After his body was destroyed in this encounter, Robo-Robotnik's consciouness was transported back to his reality on board a vacent space station. He managed to rebuild himself using a piece of the Giant Borg, after stealing its location from his Mobius Prime counterpart's memory. After defeating the Freedom Fighters in his dimension, Robo-Robotnik discovered Dr. Ivo Robotnik had died in the Mobius Prime dimension. He decided to travel back to this reality to "fill the void" in both his and Sonic's life, effectively replacing the despot dictator's role after his death. Since then, Robo-Robotnik was deroboticized by the Bem, becoming Dr. Eggman, and acting as the primary antagonist in this reality.

Origin
Early in 3235, another Robotnik from an alternate reality appeared, calling himself "Robo-Robotnik." In this 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 biological faces. This proved a mistake when the cyborg Freedom Fighters retained their sentience and rampaged through Robotropolis. In a last-ditch effort to save himself, Robotnik turned his own Roboticizer on himself. This new Robotnik was apparently so dangerous that Cyborg Sonic fled his reality to seek help from Sonic of Mobius Prime (the main character of the comic books), especially now that he was seeking out the Giant Borg machine; a device which could threaten every dimension. (StH: #19)

Coming to Mobius Prime
With the help of Evil Sonic, Robo-Robotnik succeeded in discovering its location. He piloted the Borg by himself, wreaking havoc until he was struck down by thousands of alternate dimension's version of Sonic, each arriving from their own reality to pummel the Borg to pieces. The scattering of the Giant Borg seemingly destroyed him, leaving him nothing more than a severed robot head. Unbeknownst to anyone, he survived by transferring his digital mind to a derelict space station, where he remained in stasis. (StH: #19)

A short while later, the Dr. Ivo Robotnik of Mobius Prime was seemingly vaporized by E.V.E., a machine that was designed to kill Sonic, but ended up turning on Robotnik instead. Rather than dying, Robotnik was actually sent to the alternate reality of Robo-Robotnik, where he met his robot self onboard the space station. Robo-Robotnik appeared on a monitor and explained that the space station itself was still incomplete, keeping him mired in space until his systems run down. In response, Robotnik-Prime convinced him that even if they failed in this world, by sending him back to his own universe, they both still stand a chance.

This meeting inspired Robo-Robotnik, and while he assisted Robotnik-Prime in returning home, he stole his memory regarding the location of the Giant Borg's piece hidden in his own reality. He used this piece to construct an artificial body for himself, and proceeded to bombard the planet with nuclear weapons, wiping out the Royal Family and the Freedom Fighters. (StH: #22)

With all of his enemies killed in his reality, Robo-Robotnik finds himself with nothing to do. He soon learned of Robotnik-Prime demise, and decided to take advantage of the death of his "other self" by ruling Mobius in his stead. After conspiring from the shadows for several months onboard a group of satellites he brought with him from his own reality, Robo-Robotnik, wearing a skin disguise to fool everyone into thinking he was Robotnik back from the dead, eventually revealed himself after luring Sonic and the Freedom Fighters to his satellite in space. Sonic fought Robo-Robotnik on an assembly line, which ended with the latter being doused with acid, removing his disguise and exposing his deception. (StH: #75)

The Freedom Fighters enlisted the help of Snively to blow up the orbital platform with Robo-Robotnik in it. With his body destroyed, Robo-Robotnik transported his consciousness into a new robotic body, which was hidden half a mile below the city of the newly rechristened Robotropolis. With his new body he took on the new name: Dr. Eggman. (StH: #76)

While in this robotic body, Eggman underwent a process which made it so he had the ability to roboticize anyone with a mere touch. He used this on numerous people, both Mobians and Overlanders, including this reality's version of his brother, Colin Kintobor, Nate Morgan, and Snively. Unlike Mobians however, the roboticized Overlanders became nothing but metallic statues, unless they desired to become roboticized, as in Snively's case. He also had the ability to have his coinsciousness transported to a new body each time his current one was destroy, a technique he was forced to take advantage of on numerous occassions. (StH: #100, #105, #110, #116, #117)

Shortly after an encounger with the Fearsom Foursom, Eggman finds himself captured along with Snively, Sonic and Tails 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. After loosing to Mecha Sonic and Mecha Tails, both Eggman and Snively are sent back to Mobius in their organic forms. Additionally, they are unable to re-roboticize themselves due to an after-effect of the Bem's deroboticizer. (StH: #118)

After the Bem
Not long after this, Mobius is attacked by another alien race called the Xorda. The Xorda had attacked Mobius over twelve thousand years ago, when the planet was still known as "Earth", and had thought all life had been wiped out. When the Xorda encountered ships carrying Overlanders, the descendants of humans, they returned to Mobius to find the planet still inhabited. When the Xorda attack Eggman's forces, he realized the Xorda posed a legitimate threat, and asked for an alliance with the Kingdom of Acorn. With the help of Sonic and Sally, the Xorda ship was forced to retreat. Unwilling to leave the job unfinished, the Xorda left behind a device intended to destroy the entire world and solar system called, known as the Quantum Dial. Sonic successfully prevented the device from going off, but was teleported to another side of the universe in the process, leaving everyone to believe he died. (StH: #124. #125)

Now unopposed, Eggman seized the opportunity to re-conquer sections of Mobius, which were lost after the original Ivo Robotnik's death, thereby creating the Eggman Empire. He struck 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 changed his main base of operations from the nuclear wasteland of Robotropolis (which was destroyed in a nuclear strike by Station Square) to New Megopolis. (StH: #110, #130, #169)

Most recently, Eggman launched a large-scale offensive against the Kingdom of Acorn, using his massive Egg Fleet to inflict heavy damage via aerial bombardment, effectively destroying the entire Kingdom and Freedom HQ. During this attack, he managed to capture the entire population (bar Sonic, Tails, Knuckles and Amy), transporting them to his Egg Grape Chambers to be used as a source of fuel for his city. He also engaged in a one-on-one duel versus Sonic wearing his newly created power armor called the Egg Beater, thrashing Sonic physically and psychologically before he departed. Eggman came to regret his decision when the four survivors launched a rescue mission that foiled his plans and liberated the prisoners. The Mobians were subsequently transported to New Mobotropolis when NICOLE altered the programming of the Egg Beater to transport them there, as opposed to the Egg Grabe Chambers. In retaliation, he redeployed his Egg Fleet, which was lead by Snively, to attack the city's shield while he fought Sonic in his Egg Beater. The combined might of Sonic, the Freedom Fighters and the Chaotix proved too much for his power armor, resulting in its destruction, cauing Eggman to flee. (StH: #175, #176, #177)