Robotnik Empire (Sonic Underground)

The Robotnik Empire is a political body that appears in Sonic Underground. It is a totalitarian regime ruled by the infamous Dr. Robotnik. It was established on Mobius shortly after Robotnik's takeover of the planet, with its capital city being Robotropolis. Its main enemies are the resistance and their numerous allies. Regardless, the Robotnik Empire continues to encompass much of Mobius.

History
Just after Queen Aleena Hedgehog's children Sonic, Sonia and Manic were born, Dr. Robotnik surfaced with an army of robots and technological machines which he used to seize power over Mobius, overthrowing Queen Aleena and making the captured city of Mobotropolis his seat of power, which he renamed Robotropolis.

With his takeover, Robotnik made the royal family outlaws and changed the government. As the source of his monkey, Robotnik largely ignored the aristocrats and left them to play, while the poorer inhabitants were turned into slaves with roboticization. Though many citizens are still free, they live under the constant threat of roboticization. In time however, the resistance arose to wage war with the Robotnik Empire and free Mobius, with Queen Aleena's children becoming the resistance's leaders years later.

According to the Oracle of Delphius and other prophecies, the Robotnik Empire will come to an end when Queen Aleena and her children reunite to form the Council of Four and bring down Robotnik.