Question: what the difference between dr robotnik and eggman?
Answer: Though the character was always named Doctor Eggman in Japan, Sega of America changed his name to Doctor Ivo Robotnik when localizing Sonic the Hedgehog. ... 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.