Dr. Eggman is a version of Dr. Ivo Robotnik from another zone. He first came face to face with Sonic the Hedgehog of the Mobius Prime reality when he was attempting to assemble the Giant Borg battle machine. After his body was destroyed in this encounter, Robo-Robotnik's consciouness was transported back to his zone on board a vacant space station. He managed to rebuild himself using a piece of the Giant Borg, after stealing its location from his Mobius Prime counterpart's memory. After defeating the Freedom Fighters in his zone, Robo-Robotnik discovered Dr. Ivo Robotnik had died in the Mobius Prime dimension. He decided to travel back to the Mobius Prime reality to "fill the void" in both his and Sonic's life, effectively filling the despot dictator's role after his death. Since then, Robo-Robotnik was deroboticized by the Bem, becoming Dr. Eggman, and acting as the primary antagonist in the Mobius Prime reality. After suffering numerous setbacks, Dr. Eggman's mental stabilty went into steady decline.
Doctor Robotnik Mark II