Optimus Prime: was in Stasis Lock during the battle against the Cybertronian Empire at The Hub, after his defeat of Galvatron. He lamented the loss of Earth, a planet accidentally brought into their conflict. He would recover before the final battle against the Predacon Armada, but took more of an advisory and tactical role than frontline combat duties.
The battle was would be won, but Optimus could not see it as a victory, but more a sad taste of warfare for the next generation of Cybertron’s sons and daughters. He handed control of the Autobot/Maximal forces to a Council of Elders, old friends and allies that had returned from the Matrix to lead the new faction. The war had been eons long, and its true cost was incalculable.
Prime had been chosen to lead the Autobots to victory over Megatron, and the peace most thought impossible - but here they were. His work was done and it was time for him to rejoin the All Spark and stand proud beside the Primes that had come before. The Matrix guided his hand in choosing, not an Autobot, but a Maximal, to pass the Matrix on to. Maxim, a powerful warrior, (and in time a great leader) became Maximus Prime.
Optimus sought rest for his Spark, and voyaged in mind and body, through J’nwan, to the heart of Primus, leaving his descendants in good hands, and greeting old friends and foes with his own, in peace.