Eggmen are a different evolution of Humans. They evolved from Neandertals and build a massive empire sprawling across half the globe. Unfortunately the Eggmen didn't like the cold, so when the Ice Age arrived, they packed up and left Earth or DOX as was known back then. They left hints of their race behind. One for instance was Doxian, which mankind has adopted and renamed English.
All hail the Empire Of Eggman!
G.U.N. - Guardian Units of the Nation.
Maniacal military organistion, which appears in Sonic Adventure 2.
Military forces include: Helicopters similar in appearance to Russian Hinds, Mechs armed with machine guns, rockets, and laser cannons, Hundreds of robot drones called Hunters, who all seem to have very small feet, and thousands of soldiers, agents, commanders, thieves, news reporters, door-to-door salesmen, etc.
G.U.N. are responsible for the deaths of the research scientists aboard the Space Colony ARK.
Because of this, they will pay.