Primus is the creator-god of the Transformers. An ancient and ethereal being whose origins date back to the beginnings of the universe itself, Primus is a multiversal force for good, his life force existing across multiple realities and infinite alternate universes. In each one, he is the final defense against his fallen sibling, Unicron the Chaos-Bringer.
Primus eventually transformed himself into the planet Cybertron; from its surface, his creations have risen to defend and patrol the galaxy. Within the depths of Cybertron, the mega-computer Vector Sigma serves as his internal mainframe, and a gateway for select Transformers to access his power. A portion of his lifeforce resides within the Matrix, which often determines the leader of the Autobots. Prophecies of a war to come were written down in his holy covenant as well. The spark of each Transformer is a small piece of Primus's essence, and together they form his lifeforce, the AllSpark.
Though wise and powerful beyond measure, Primus is neither infallible nor without weakness. At times he has been deceived by mere mortals, has made miscalculations which jeopardized all of existence, and has been betrayed by one of his earliest creations. Indeed, even the intended agents of his grand plan, the Transformers, have all too frequently become mired in endless civil war. Still, in most realities he has managed to hold the line against Unicron and other threats, either directly or through his innumerable children, the Transformers.