Doctor Ivo "Eggman" Robotnik (Classic)

SegaSonic the Hedgehog
Sometime in the past, Eggman managed to capture Sonic the Hedgehog, Mighty the Armadillo and Ray the Flying Squirrel. However, the trio eventually escaped, which led to the destruction of Eggman's prison base.

Sonic Generations
In Sonic Generations, during the timeframe of the West Side Island incident, Eggman encountered Sonic the Hedgehog onboard the Death Egg. Eggman proceeded to fight Sonic in his Death Egg Robot, but was defeated. In the aftermath, Eggman got kidnapped by the Time Eater. As it turned however, the Time Eater was controlled by Modern Eggman, Eggman's future counterpart from another dimension, who needed Eggman's help perfecting the Time Eater, which had the power to let both Eggmans undo their previous defeats at the hands of their worlds' native Sonic by erasing the Sonics' actions from history altogether so they would be victorious in the present. More than happy to help his counterpart realize that plan, Eggman teamed up with Modern Eggman and began helping him lure Sonic and Modern Sonic into Modern Eggman's traps. It was presumably during this time that he learned from his Modern counterpart that he would go by his nom de guerre of "Dr. Eggman" instead of "Dr. Robotnik" as well as adopting said non de guerre himself.

Eventually, Sonic and Modern Sonic, along with Tails and Modern Tails, tracked Eggman and Modern Eggman down to their lair. There, the heroes found out about the Time Eater's true origin when the doctors revealed themselves and their plan, intending to dispose Sonic from time (although Eggman ended up disturbed that he might become crazy when witnessing Modern Eggman breaking down into hysterical laughter). The Eggmans proceeded to attack the Sonics with the Time Eater, and managed to knock them out. However, both Sonics would transform into [./https://sonic.fandom.com/wiki/Super_Sonic_(Classic_Sonic's_world) Super] Sonic when their friends showed up to cheer them on. After enduring an intense battle, Eggman and Modern Eggman ended up being defeated when the Super Sonics destroyed the Time Eater, which undid all of their work on rewriting history.

Finding themselves stuck in the White Space, Eggman and Modern Eggman went about looking for a way out. Eventually, Eggman asked Modern Eggman what time it is, before the latter irritably reminded him that he can't tell him what time it is as time does not exist in the White Space. After arguing about whether or not they would ever win, Eggman thought that maybe he should instead pursue his "teaching degree" after these events, to which Modern Eggman agreed as he enjoyed telling people what to do, much to Eggman's exasperation.

Sonic the Hedgehog 3 & Knuckles
In Sonic the Hedgehog 3 &amp; Knuckles, Eggman crash-landed on Angel Island in his Death Egg. There, he tricked Knuckles the Echidna, the guardian of the island and its Master Emerald, to keep Sonic and Tails off his back while he repaired the Death Egg. When Eggman re-launched the Death Egg however, the space station was brought down to Angel Island again by Sonic and Tails. Having not given up let however, Eggman stole the Master Emerald and used it to re-launch the Death Egg again. However, Eggman soon after got defeated by Sonic and Tails, who destroyed the Death Egg.

Sonic Mania
In Sonic Mania, after Sonic and Tails had defeated Eggman, the evil scientist detected a strong energy source coming from Angel Island, prompting him to send his five elite Egg-Robos, the "Hard Boiled Heavies", to go and retrieve the source. Soon after, Eggman found himself in Green Hill Zone, where he faced Sonic, Tails and Knuckles in his Death Egg Robot. He was soon defeated though, and eventually came across his Hard Boiled Heavies, who had been upgraded by the energy source. Seeing as the Heavies would no longer listen to him, Eggman took the energy source, the "Phantom Ruby", away from them and used its power to send Sonic, Tails and Knuckles, who were secretly eavesdropping on him nearby, away.

Over the next period, Eggman used the ruby to restore Little Planet to its mechanized state. Afterward, he began building a robotic fortress known as the Titanic Monarch on Little Planet. Along the way, Eggman made several attempts to stop Sonic and co., but was defeated each time. He would also occasionally use the ruby to displace the heroes when they began catching up to him.

It was not long until Sonic, Tails and Knuckles chased Eggman down to his base inside the Titanic Monarch. However, the mad doctor was prepared for them. He fought the trio using his Phantom Ruby-empowered Phantom Egg while sending the heroes to also fight the members of the Phantom Heavies. Unfortunately for Eggman, he was still defeated. Upon his defeat, however, the Phantom Ruby sent Eggman and Sonic to an unknown location. There, the Phantom King (the upgraded leader of the Hard Boiled Heavies, the Heavy King), stole the ruby for himself. Eggman was not prepared to give up easily though, and used his Klepto Mobile to combat his traitorous minion. In response, Sonic used the Chaos Emeralds to transform into Super Sonic to fight them both. After the Phantom King was defeated, Eggman was delivered the final blow by Super Sonic, putting his mech and his plans to ruin.

Sonic Mania Plus
In Sonic Mania Plus, some time after losing the Phantom Ruby, Eggman attacked [./https://sonic.fandom.com/wiki/Sonic_the_Hedgehog_(Classic_Sonic's_world) Sonic] and his group of friends in Green Hill Zone with his Death Egg Robot. Though he was soon defeated, he came across his revived Hard Boiled Heavies, who had gotten their hands on the Phantom Ruby again, in the aftermath. Seeing that the Heavies again refused to listen to him, Eggman took the Phantom Ruby from them and used its power to send Sonic and his friends, who were secretly eavesdropping on him nearby, away.

From there, Eggman retried his previous plot by using the ruby to restore Little Planet to its mechanized state. After that, he rebuilt the Titanic Monarch on the miniature planet. Along the way, Eggman made several attempts to stop Sonic and co., but was defeated each time. He would also occasionally use the ruby to displace the heroes when they began catching up to him.

Eventually, Eggman got chased into the Titanic Monarch by Sonic and his gang. There, the mad scientist attempted to fight the group using his Phantom Ruby-empowered Phantom Egg, but was defeated again. Upon his defeat however, the Phantom Ruby activated, creating a rift that began sucking in the surroundings. Eggman attempted to escape the rift on a jet sled, but got knocked into it by Sonic and co. when the heroes escaped the rift in their Super States.

Sonic Mania Adventures
During Sonic's absence, Dr. Eggman managed to collect four of the Chaos Emeralds that laid buried on Angel Island. When Sonic returned to Angel Island, Eggman made Sonic follow him to a clearing where he had set a trap for Sonic by flying over Sonic with a Capsule full of kidnapped Flickies in the Egg Mobile. Leaving the Capsule in the open, Sonic got caught in Eggman's trap when he opened the Capsule. As the Capsule turned into a timed bomb, Eggman appeared to gloat to Sonic. Eggman was then about to leave Sonic to get blown up until Sonic showed him the Chaos Emerald he had. Eggman promptly tried to steal it, but got lured into his own trap by Sonic, who proceeded to break free. Before Sonic left though, Eggman almost guilt-tripped Sonic into releasing him before his bomb could blow up. However, Eggman dropped his handheld, which revealed his plan to cheat Sonic and take his Emerald. Sonic thus accelerated the countdown on Eggman's bomb and left Eggman to have his bomb blow up in his face.

Detecting the next Chaos Emerald on the island, Eggman went to excavate it. While at work, he was confronted by Sonic, but Eggman repelled Sonic with his excavation mobile. Before Eggman got the Emerald however, Sonic returned with Tails. As the heroes smacked Eggman around, the doctor almost got Sonic with his excavation mobile, only to be foiled by Tails. The two heroes then critically damaged Eggman's excavation mobile, which led to Eggman getting sent flying when his machine blew up. Landing on Angel Island's beach, Eggman discovered via a Badnik that Knuckles had the Master Emerald out in the open, and began making an evil plan that involved the Tornado. Boarding the biplane, Eggman used it to take the Master Emerald while Knuckles was distracted. As Eggman flew away with the massive gem, Knuckles assumed that Sonic was behind the theft since all he could see was the hedgehog's plane taking the Emerald.

Having returned to his base, Eggman gleefully witnessed the arrival of Metal Sonic (who had found the last Chaos Emerald), Sonic, Tails, Knuckles, Mighty, and Ray. When Metal Sonic returned, he gave the final Chaos Emerald to Eggman. Then, upon Sonic and Tails' arrival, Metal Sonic took the duo's two Chaos Emeralds. Eggman then left Metal Sonic to harness the power of all the Chaos Emeralds and take Sonic on. Even as Mighty and Ray entered the fray, the doctor remained undeterred. However, he was shocked when Tails trapped Metal Sonic and stripped him of all the Emeralds. Despite this setback, Eggman used his backup plan by having Metal Sonic harness the power of the Master Emerald. Unfortunately, Knuckles arrived and punched both Eggman and Metal Sonic out of Eggman's lair before anything could happen. Crashing in the jungle with Metal Sonic, Eggman cursed his defeat. When Metal Sonic would not work either, Eggman tried to make him rise by kicking him. When that did not work, a sour Eggman decided to abandon him in the jungle and left in a huff.

Several months later, during winter, Eggman heard someone use his doorbell. When Eggman went out to check his door however, all he found was Metal Sonic with a bow on his forehead and a flower in his hand. After examining Metal Sonic and his flower, Eggman decided to take Metal Sonic back and took him into his lair.

Appearance
Dr. Eggman is depicted as being rotund in appearance, with black pants and leggings, white gloves, a bald head, pince-nez glasses with blue lenses, a bright red nose, and a very bushy auburn moustache. He also wears a red shirt with an oversized yellow collar and gray buckles on his pants.