Primus is a singularity existing across the Multiverse. Usual attributes of Primus in the various universal clusters include being the arch nemesis of his evil twin brother Unicron, possessing Cybertron as a body and being the creator of the Thirteen.
Primus manifests himself in radically different ways within the many Universal Streams of this cluster. In some streams he is the sole creator deity of the Transformers, in other streams he began as the assistant Primacron. He usually communes with other individuals through the supercomputer Vector Sigma located at the center of Cybertron.
In the universal streams of the Aurex cluster, Primus is the living energy core of Cybertron, as well as the originator of the precious and ancient fuel, Energon. He utilizes Cybertron as a transformable body.
In the Uniend cluster, Primus is arch-nemesis of his twin brother Unicron and the creator deity of the Transformers. Both Autobots and Decepticons invoke his name religiously. He created the original thirteen, and together they managed to defeat Unicron, who was in his weakened state and left to drift throughout the galaxy. Primus then merged with the already-existent Cybertron's core and lay dormant for many millions of years. As Cybertron entered and continued a civil war, the battle's began to poison the planet's core in turn infecting Primus. Luckily Orion Pax arrived to help clear the core of its affliction. Primus, sensing Orion's pure spark, bestowed upon him the Matrix of Leadership, containing the essence of the Thirteen original Primes, turning Orion into Optimus Prime.
- The original form of Primus in Marvel Comic continuity is similar to Hot Rod/Rodimus Prime.
- The myth of Primus and Unicron bears a passing resemblance to the Zoroastrian myth of Ahura Mazda and Ahriman.
- The idea of Primus transforming bears some resemblance to an early script for the original movie, in which Optimus Prime merges with Cybertron and transforms into a super robot to defeat Unicron.
- In the cartoon Ben 10: Alien Force, there is an actual episode and artificial planet named "Primus".