Optimus prime is an autobot in g1 continuity Before the war, Optonix was the pride of the Autobot police force. When the decepticon rebellion began and Sentinel Prime was killed, he passed the matrix of leadership to Optonix and he became Optimus Prime. When the decepticons conquered Cybertron, Optimus and a small group of Autobots (who by this time had changed from Law enforcement to freedom fighters) escaped Cybertron in the Ark. Notes: Optimus Prime is believed to be the chosen one. The one who will "Light our darkest hour."