Design for sentinel maximus and primal prime
Venturing deeper into the citadel, the autobots encounter the next guardian created after dragonstorm. long ago maximus merged with the allspark's vessel to mask it's energies but now transfers that duty to Optimus prime, forging the matrix of leadership, freeing maximus to live the life she always wanted under a new name and body as primal prime, she and the matrix are one and the same even if not physically connected anymore, and she yearns to explore the world she spent so many years protecting
Sentinel maximus is the previous name of primal prime before she remade herself to experience the world (listen not everyone has good taste in names but be happy for her either way)
Having guarded the allspark alone for many years, she and dragonstorm were the only ones active when the six clan entombed them underground so many years ago, but the six clan didn't stop there, they continued to invade the citadel for years to get their hands on the allspark, until sentinel, in an attempt to ensure it's power couldn't fall into the wrong hands, transfered the allspark into a new vessel and merged with it, the allspark container entirely replacing her own spark, and blurring the allspark's wants and needs with her own to such an extent that there isn't any meaningful difference between them. The allspark, now contained within optimus prime's matrix is as much an expression of her as she's an expression of it
Before the guardians were entombed underground, the allspark was making progress on something it had started to make from the moment it struck our soil, but the magnitude of this creation was so vast it took years to become noticable, and when it did, the six clan struck, seemingly attempting to take the allspark for their evil schemes but in truth tarantulas knew what was being born underground and knew that it's awakening at that point would spell doom to everyone on earth, and when sentinel merged with the allspark and saw it's plans, she knew it too, but unable to stop what already started, she used her powers to slow it down. And entirely focused on doing that until the autobots found the citadel in the modern day
Moved not by the mistress of flame's claims of their godhood but rather claims of their good deeds, she reached out into the autobot's minds and sensed a reservoir of wisdom carried by optimus that marked him as fit to carry the allspark, but his vessel, neither like the emberstone ,nor his own body like maximus, would be the matrix given to him by the mysterious stranger that saved his life all those years ago. Embedding the allspark within his matrix it became the matrix of leadership, and sentinel maximus was relieved from duty, passing on her mission to optimus prime while she got to reinvent herself in a new feminine body, as primal prime (inspired by the name of her sucessor although she doesn't really get the significance of the word prime, not being from space and all that)
Primal prime yearns to explore the world in the time she has left to live, as after having become one with the allspark her life force is split between her body and what's housed inside the matrix so one day she knows she'll have to be absorbed into it completely to unlock it's full power and wants to live life to the fullest before that happens, although she's incredibly ancient she's really fond of young people and wants to be up to date on current trends, while the autobot leaders are off doing important world saving work, she's off enjoying the world they're saving one road at a time, in the process she's joined the trottlebots and struck a deep friendship with hot rod.
