Leader of the Autobots, respect the ass kicking trucker
Transformers: The Movie 1989: Optimus Prime began his life as an Autobot named Orion Pax during the Golden Age of Cybertron nine million years ago. Together with his girlfriend Ariel and his best friend Dion, Orion was a dock-worker who had the simple job of unloading and storing shipments of energy that came from a power planet up-river. But the times in which Orion lived were strange ones: a new breed of robot had recently appeared on the planet, with strange robot-mode flight powers that led Orion and Dion to idolize them. Ariel wasn't so sure, having heard rumors that the flying robots' leader had recently perpetrated an attack on an outer city.
Better get used to dying horribly, buddy.One day, Orion was going about work as usual when an unfamiliar group of five robots arrived on the docks, and Orion, wondering if they were new workers, introduced himself and his friends. At that moment, all attentions turned skyward as a group of the flying robots soared by overhead. Both Ariel and the newcomers urged caution in dealing with the fliers, but Orion waved off their concerns, and returned to work. Before long, Orion was shocked when he was approached by Megatron, leader of the flying robots, who claimed to be looking for a place to store his wares. Overcome, Orion showed Megatron around the warehouses and explained that they were used for storing energy... at which point Megatron ordered his followers, the Decepticons, to attack and steal it all! When Orion took a shot to the shoulder from the Decepticon leader, Ariel rushed to his defense, but was hit by another blast from Megatron. The enraged Orion lunged at Megatron, but was shot down by yet another blast from the Decepticon's cannon. While Megatron and the Decepticons set about pillaging the warehouses, the five robots Orion had met earlier carried his body away, in hopes of finding someone to repair him. They came upon the Cybertronian machinesmith Alpha Trion, who reluctantly decided to subject Orion to a new reconstruction process he had developed, which would rebuild the Autobots' frail bodies into battle-hardy configurations so that they could battle the Decepticons on even footing. Thus it was that Orion Pax became Optimus Prime, the new leader of the Autobots, and was given the Matrix of Leadership, which Alpha Trion had kept safe since Megatron had killed its previous holder. While Alpha Trion set to work on rebuilding Ariel into "Elita One" using Prime's schematics as a basis, Prime confronted Megatron, introducing himself as the Decepticon's "worst nightmare". A mighty battle ensued, which came to an end when the warehouse's fuel stockpiles were blown up by the five enigmatic Autobots, who disappeared. War Dawn
Over the following five million years, Optimus Prime led the Autobots in a steady war of attrition that gradually drained Cybertron of almost all of its energy. In order to continue the fight, Prime arranged for an interstellar expedition to search for energy on other planets. Loading his best and brightest aboard a huge spacecraft, Prime was the last to board, but was stopped by a cry from Elita One, who came running up to the launch platform. Prime told her that he would return for her as soon as he could, but Elita was intent on joining Prime on the mission. No debate was to be had, however, as a Decepticon attack on the platform caused an explosion that seemingly destroyed Elita. Crestfallen, Prime boarded the spacecraft and ordered a take-off, unaware that Elita had, in fact, survived.
TFTM-ROTF: Optimus Prime is the leader of the Autobots. Long ago, he was the humble leader of Cybertron's sciences division, which studied the All Spark, 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 All Spark and conquer other worlds, Optimus assumed his proper title and rallied the Autobots to stand against the Decepticons.
As obsessively as Megatron strives to achieve his objective, Optimus is equally as dedicated to stopping him, even at the cost of his life, his world, and—if necessary—his own people. It was on his order that the All Spark was jettisoned into space, dooming Cybertron to a slow death and his people to nomadism. The sacrifices he has made weigh heavily on his spark, but they must be done, for there is no other choice. He knows the ambitions that lurk in Megatron's spark, and they must never see the light of day. Lives must be kept free from the threat of Megatron's tyranny, no matter the cost.