Primus

Primus is the living creator-god of the Transformers. His body is actually the planet Cybertron itself. It was Primus who first bestowed the Matrix of Leadership on Optimus Prime. Primus is the twin brother of the Chaos Bringer, Unicron, whom he had been at war with for centuries. It was Primus who created the Thirteen Primes which led to Unicron's defeat in the first place. For the next couple million years Primus remained offline, leaving his safety to the Autobots, who thwarted two major attempts on Primus' life by Unicron himself.

Primus is a special guest star character in Transformers Prime: Galvatron's Revenge, as he appears near the end to assist the ultimate defeat of Unicron and his Heralds.