Dr. Robotnik the ultimate megalomaniac on Mobius. But he was not always like this he
used to be peaceful scientist Dr Kintobor. Dr Kintobor was working on his machine the random omni chaos compressor (R.O.C.C machine) , this machine was meant to absorb all the evil  energy on mobius and compress it into the  SIX chaos emeralds (note: the master emerald is with knuckles on the floating island). Kintobor got hungry and so went to the fridge but all he found was a rotten egg. He picked it up and carried on towards his machine, when he tripped over some loose wires and activated the machine, the machine was unstable and Kintobor fused with the evil chaos energy and the rotten egg and became the evil Dr Robotnik or Eggman. He vowed to take over mobius and be the supreme ruler, sonic vowed to stop him. Regardless of Robotnik's IQ and his mechanical flare he cannot manage to concoct a plan or robot which can defeat his arch rival sonic the hedgehog.