Dr Robotnik is a despotic mad scientist bent on turning all life on planet Mobius into robotic slaves for him to rule over and the archenemy of Sonic the Hedgehog. By the time the series starts, Robotnik has already conquered Mobius and converted most of its inhabitants into robots, with only a small group of Freedom Fighters led by Princess Sally and Sonic to oppose his tyrannical reign. He has an incompetent nephew named Snively and a pet robotic rooster named Cluck.