Optimus Prime, formerly known as Orion Pax, is the leader of the Autobots. Long ago, he was the novice to the Great Sentinel Prime and the humble leader of Cybertron's science division, which studied the AllSpark and were protected by Lord High Protector Megatron's military. When Megatron was corrupted by the Fallen, Optimus discovered that he was the last of the Dynasty of Primes hidden away when the Fallen destroyed their lineage. In response to Megatron's attempts to seize the AllSpark and conquer other worlds, Optimus assumed his proper title and rallied the Autobots to stand against the Decepticons. Before the disappearance of Sentinel, Optimus is handed the leadership of the Autobots.