The Egg Emperor was a mech created by either Dr. Eggman or Neo Metal Sonic - the powered up form of Metal Sonic - and was used by Neo Metal Sonic while disguised as Eggman at some point in the recent past. (StH: #1)
Piloted by Neo Metal Sonic
At some point in the recent past, a battle happened between Sonic the Hedgehog and Neo Metal Sonic who was impersonating Eggman. This time, the fake Eggman was piloting the Egg Emperor mech, but Sonic and his friends defeated the faker. (StH: #1, #7)
- The Egg Emperor was based on the machine of the same name in the Sonic the Hedgehog video game series, where it first appeared in Sonic Heroes as the final boss of each of the four main stories. It was unnamed in the comic, but is considered tier 2 canon by this site's canon policy, as it does not contradict already established canon from tier 1.