Board Thread:General Discussion/@comment-1031724-20160828014723/@comment-1031724-20160907032258

Also of note: Sonic first gives Robotnik the nickname "Eggman" in Sonic Adventure, so any games where characters call him "Eggman" must be set after (He still calls himself Robotnik in Sonic Adventure, but starts calling himself Eggman in Sonic Adventure 2, his theme song even goes "I am the Eggman"). The game can still call him Eggman as long as characters don't (like Sonic 4, if I remember correctly)