Many years ago, an "accident" saw Doctor Kintobor turn into the evil Doctor Ivo Robotnik. Soon after, he would go on to take over Mobius and rule through harsh treatment of his subjects, the only resistance coming from Sonic the Hedgehog and his Freedom Fighters. In time, the people of Mobius realised they could stand up to this threat and began to revolt whilst Robotnik was away, seriously undermining Grimer's caretaker abilities. However, it wasn't until an electromagnetic pulse caused by the Black Asteroid's explosion ended Robotnik's reign for good.