Why is Dr. Robotnik called Eggman?

The character began as a reject. Among Naoto Ohshima's entries in Sega's mascot contest was a round man in pajamas resembling Theodore Roosevelt. Sonic won the contest, but Sonic Team thought the discarded design was excellent, retooled him as the villain, and built him as Sonic's opposite: machinery and development against nature, a character easy for children to draw. In Japan he was, from the first game, Doctor Eggman, the name printed in the Japanese instruction manual for Sonic the Hedgehog.

The second name has a named author. Dean Sitton of Sega of America changed the character's name to Doctor Ivo Robotnik while localizing the game, and the English manual introduced him under that full name. Series producer Takashi Iizuka explained the process to Game Informer in 2016, and it was not a process: "They just kind of went off and did it. It became super popular and everyone in the West kind of learned about the character as Robotnik." The split then ran through the whole classic era, one villain with two names divided by an ocean, each audience certain its name was the real one.

Iizuka also performed the repair, and described doing it: "We really didn't want to have anyone in the Sonic universe with two names. To us, he's Eggman, but in the rest of the world he's called Robotnik. We wanted to unify that into one name moving forward. This is something I actually did in the Sonic Adventure series. I made it so that we understand the character's name is Robotnik, but his nickname is Eggman." The English version of Sonic Adventure in 1999 was the first to call him by both names, and later English releases settled on Eggman as the everyday name. Yuji Naka has given the same reconciliation from the other side: Robotnik is the character's true family name, and Eggman is a nickname alluding to his shape.

The joke completed itself in time. Later games, Sonic Frontiers among them, establish that the doctor has accepted the Eggman name outright, wearing his enemy's mockery as a title. The Western name did not die, either: it survives inside the merged canon as his family name, borne by his grandfather Gerald Robotnik and his cousin Maria. Two offices named one villain in 1991. The fiction, given thirty years, found room for both.