Doctor Eggman

Doctor Eggman is the primary antagonist from the Sonic the Hedgehog series. He is an obese scientist with an IQ of 300 who wants to dominate the world and create his Eggman Empire, but his plots are thwarted by Sonic the Hedgehog and his friends. He is one of the Sonic the Hedgehog characters present in Archie Comics' crossover Worlds Collide.

Story
Note: This article only covers his appearance in Archie Comics' Sonic the Hedgehog and Sonic Universe comic book series.

Background
Doctor Ivo "Eggman" Robotnik (born Julian Kintobor, later known as Dr. Ivo Robotnik; also known as Robo-Robotnik v2.0, Robotnik Mach II and Eggman) is a version of Dr. Ivo Robotnik from an alternate timeline of Archie Comics' Sonic the Hedgehog comic series. In his native universe he was defeated by the Freedom Fighters after he roboticized himself, only to survive by uploading his digital consciousness to an unfinished space station he had constructed. He languished there for years, facing eventual shutdown, until a chance encounter with Dr. Ivo Robotnik of Mobius Prime who had been inadvertently teleported to Robo-Robotnik's future reality by E.V.E.. This meeting inspired Robo-Robotnik to continue fighting and eventually managed to rebuild his body—then bombarded Mobius with atomic weapons, killing his nemesis King Sonic and the entire Royal Family. With no one left to fight, and having discovered that the Robotnik of Mobius Prime had been killed, he traveled to Mobius Prime to "fill the void" in both his life and that world's Sonic, and became known as Dr. Eggman once his original robotic body was destroyed.

Eggman eventually was de-roboticized by the Bem, becoming a flesh and bone Overlander once more, but continued to act as the primary antagonist in the Mobius Prime reality. After suffering numerous setbacks to his conquest, Dr. Eggman's mental stability declined until he finally succumbed to complete madness following a major defeat by Sonic, and was subsequently locked away by Snively, only to escape and be taken into custody by his enemies. During the Iron Dominion's takeover, Eggman regained a semblance of his sanity and finally escaped from New Mobotropolis's prison after the fall of the Iron Queen. He returned to the Eggdome with Snively and the local Dark Egg Legion chapter to plan for his renewed battle with Sonic. This led to the launch of the Death Egg Mark 2, Operations Clean Sweep, Titan, Deadly Cuddles and the use of the Egg Annihilator Beam, all to destroy New Mobotropolis. All these attacks were stopped, but Eggman won the roboticized Sally to serve him.

Pre-Worlds Collide
Dr. Eggman ordered Metal Sonic (after he was repaired from his battle with Shard) to head to the interdimensional portal to meet his new partner Bass (Whom Eggman describes as a Base villain). Eggman went through it himself shortly before setting up the Genesis Wave and hoping Albert (aka Dr. Wily) was ready.

Worlds Collide
Dr. Eggman and Dr. Wily first made contact with each other when Wily's examination of the blue Chaos Emerald caused a connection between their dimensions. Realizing the simularities of their situations, they began to work together, creating the Skull Egg Zone and the Wily Egg as a base of operations. Their next step was to unleash the Genesis Wave on both worlds, enabling them to kidnap Sonic's friends to create the Roboticized Masters to acquire the remaining emeralds. After Mega Man and Sonic teamed up, they began to construct the Egg-Wily Machine X as a counter-measure. Eggman later decided to abandon Wily and steal the Wily Egg when push came to shove (with Wily having mutual feelings regarding Eggman on the matter, albeit in reverse), although he promised that he would carve Wily's face into a continent in remembrance of him. Eggman later tried to kill Dr. Light when he realized he had leaked to Rouge information relating to the Wily Egg, as well as his trying to contact the heroes by throwing him out of the Wily Egg. However, this soured his friendship with Wily beyond repair.

In the end, he sabotaged Super Sonic's attempt to restore their world, causing them to return to an altered version of their home.

Post-Worlds Collide
Dr. Eggman, along with Orbot and Cubot ended up in the Efrika Plains along with the remains of the Egg-Wily Machine X. Eggman, annoyed by his recent failure, blamed Al for everything.

They, along with Sonic, Blaze the Cat and later Tails are the only ones who can recall Worlds Collide.

He soon discovered that his interring with Sonic resulted in their planet beginning to tear apart.

Additionally, his history was altered in that he has always been Sonic's prime adversary instead of Dr. Robotnik. His first encounter with Wily now occurred after the events of Sonic Generations instead of Sonic: Genesis.

Pre-Worlds Unite
200 years from Sonic's time, it's discovered by Professor Von Schlemmer that Eggman's interference with Sonic's attempt at undoing the Super Genesis Wave, resulted in the creation of the Genesis Portals, with Eggman himself learning this after overhearing Silver the Hedgehog tell Sonic about them after sending an Ifrit through a portal.

Wanting to focus on how to use the portals to his advantage, Eggman sent Metal Sonic to the Cystal Desert Zone to retrieve a Chaos Emerald located there. Metal Sonic ultimately failed to do so as Silver helped Sonic stop him, and sent him through a portal to an unknown dimension that Eggman couldn't monitor. Frustrated with his robot's failure, he was unaware that Orbot is acting oddly and that he was secretly plotting with the Zeti, Zavok from the Deadly Six.

Worlds Unite
Dr. Eggman has begun construction of his new base on the Lost Hex by controlling the Deadly Six with the Cacophonic Conch until Orbot broke it. Before he could show his annoyance at Orbot's incompetence, he discovered that his minion was possessed by Sigma, who demanded for the doctor to build him a new body.

Shortly after doing so, Sigma commanded Eggman to build more for him while the latter stated that he was too exhausted to do so. This prompted the Reploid to bring Dr. Wily to the base through a Genesis Portal, much to the annoyance of Eggman, who still remembered their encounter and falling out. Both were forced into turning the fortress into a factory to produce Mechaniloids.

After being threatened into building the Unity Engines, the two doctors eventually planned to kidnap both Sonic and Mega Man to add to Sigma's army, but in reality to combat Sigma who demonstrated that he had control over the Deadly Six. The Zeti soon captured the two heroes, leaving the doctors to begin taking control of them.

While working, Dr. Eggman realized that Wily didn't recall their encounter due to Mega Man's success in restoring his world to normal. Taking advantage of this, he recapped their previous encounter to the other scientist and claimed that Dr. Light made false accusations of Eggman trying to kill him in order to manipulate Wily. The two planned for the kidnapped heroes to save each other and to assume that Sigma was responsible for their encounter, which would leave the doctors able to take the Unity Engines for themselves.

As Sigma appeared, Eggman and Wily began the roboticization process, corrupting both Sonic and Mega Man (turning them respectively into Sonic Man and M'egga Man).

Sonic Boom counterpart
A version of Dr. Eggman also exists in an alternate reality, where he comes ups with various schemes only to be foiled by Team Sonic (led by that world's Sonic the Hedgehog).

Worlds Unite
Eggman recently failed in beating Sonic during a rigged race. Shortly after, Sticks the Badger, along with the Maverick Hunters arrived in the doctor's headquarters and prompted Orbot & Cubot to let them use a device that created dimensional portals in order to pursue Sigma.

Other references to Dr. Eggman in Mega Man

 * Just like Wily is referenced in StH #247 by Dr. Eggman, Wily references him in Mega Man #23. He refers to him once by Ivo after Break Man takes leave early in the issue and then later as his new best friend before entering the portal to the Skull Egg Zone.
 * Mega Man #28 shows that Wily forgot about his encounter with Eggman and discovery of the Chaos Emeralds, but has a unexplained violent urge to stomp on a carton of eggs due to betrayal of his former partner.
 * Although not in the Mega Man comics themselves, one of Roll's costumes, as part of the 31 days to Halloween by Archie Comics artist Ryan Jampon, depicted Roll wearing Dr. Eggman's outfit as a potential trick-or-treating outfit.

Trivia

 * Dr. Eggman's Japanese voice actor was Chikao Ohtsuka, who voiced Dr. Weil in the Mega Man Zero series. Coincidentially, both Eggman and Weil had an ultimate creation known as Omega (E-123 Omega for Eggman, and Omega for Weil).
 * Coincidentally, Dr. Eggman in the beginning of Sonic Unleashed managed to pull a similar stunt on Sonic (or rather, Super Sonic) that Dr. Wily frequently pulled whenever he was defeated.