It was an agreement among the 13. The debate had gone on for hours, and while there was still some disagreement, ultimately the plan was accepted. Each of the 13 would carefully sculpt a unique spark, would create the soul of the future Prime who would one day succeed them.
Despite their great power, the Primes would not go on forever, and not all of the primes trusted the Matrix to choose the right bot every time. After all, the future of Cybertron was a massive undertaking to leave to an heirloom, even one as impressive as the Matrix. This way, there would be another step bridging the original 13 and the day were Primes would be chosen exclusively by the Matrix of Leadership. And so, they each got to work.
Prima valued strength above all. Not just physical strength, or prowess on the battlefield, but strength of character, strength of Will. The same strength that had seen him through the battles at the beginning of the Primes’ existence. He created a warrior, and when the warrior known as Nova Prime had won the war against the Quintessons, he found himself leading the planet in peace time, and he found himself ill suited for the role. All he could do was watch as Cybertron fell inexorably towards decline.
Amalgamous Prime saw flexibility as one of the key strengths needed by every leader. The ability to transform and the role it had played in defeating Unicron was proof of that. He sought to give his successor that trait, to be able to understand all sides of an argument, and compromise where needed. And when the time came for Zeta Prime to lead, his ability to compromise led him to create the high council of Cybertron, a symphony of different voices to represent all of the opinions of the people. With them to advise him, he was able to better understand all of the arguments and perspectives of the different factions. But when he was gone, the council remained. And without the wisdom of a Prime, the council lost their way.
Alpha Trion recognized the folly in giving his successor one trait to the exclusion of all others, and tried to strike a balance. After all, it had been the 13 together who had defeated the chaos bringer. To his successor, he tried to give equal parts, strength, understanding, and wisdom, hoping to give to a single bot all the strengths of the original 13. But as the 13 themselves had proved a volatile combination, Sentinel Prime was balanced too well, so much so that he could not excel too much in any aspect. As a leader at peace, he could not take charge of the ugly situation created by the council, nor could he fix it. He could only maintain the status quo. As a leader during a volatile time of festering revolution, he could not quell the angered masses rallying to Megatron’s banner. He could only reassure those who were wise enough to recognize the inherent violence of the Decepticons and their well-intentioned, but flawed and entitled demands for equality. And as a leader at war, he could not outflank or drive back his enemy. All he could do was hold the line until his fall made way for a better leader.
Megatronus was the only of the 13 who tried to forge a successor who would not be like himself. He tried to create a successor who would be even tempered, fair, always ready to fight injustice, and fearsome warrior. But no matter how hard he tried, a bit of himself always sept into the spark, tainting it with an anger that was so like his own. He tried to direct that anger, control it so that it would never be roused, except against the greatest of injustices, and it nearly worked. Had his own spark not been tainted by the corruption of Unicron, it likely would have. But that slight taint of chaos took from him the physical qualities and spiritual traits that had marked Sentinel, Zeta, and the other successors before them as Primes, preventing him from becoming a prime after his emergence from the well. It rendered him permanently unable to bear the Matrix of Leadership, regardless of whether he was worthy or not. And when the circumstances of his life had stripped from him many of the qualities that might have once elevated him, when his jealousy at being rejected turned his righteous anger into violent fury, Megatron completed the destiny that had been written for him by the very circumstance of his creation, and became the greatest enemy of the new Primes, a fitting successor for the Fallen.
In his later years, Alpha Trion suspected at various times that Orion Pax was the spark created by the 13th of his brothers. Such was his compassion, his courage, and his wisdom, so similar to 13, but the old bot could not imagine the humblest of the original Primes trying to create a successor who was so much like him. When Orion discovered the Matrix, and became the first Prime in eons to earn and carry the wisdom of the ancients, when he revealed himself as Optimus Prime, Alpha Trion instead remembered his brother‘s decision to be reborn as a Cybertronian and began to instead believe that Optimus was actually the last of the 13 reborn. It was only during the period of Optimus’ death, and the emergence of his temporary successor that he realized the truth.
13 had never intended for his reincarnated self to become a Prime. His intention had been to grow closer to their people and live as one of them, though destiny had clearly had other ideas. No, 13 had instead touched just a few sparks, rather than crafting his own, and he’d simply tweaked them just a bit. To an energetic, yellow spark, he had given just a touch of his own friendly nature and kindness towards smaller beings. To a cautious, white spark, he gave a small portion of his desire to care for the injured. To a blue, solemn, spark, imported a bit of his sense of duty to protect others. And to a fiery, orange spark, he gave a bit of his own courage. But to each spark he touched, as well as an individual tweak, he also imparted a large share of his most sacred value. That is why, when Optimus Prime chose his lieutenants among the Autobots, they always seemed to have some above average tendency to always be strong enough to be gentle.
