Very little is known about the past of the Plasmagen known as Primo, he appeared virtually out of nowhere commanding a starship of extraterrestrial Plasmagens, when their ship crossed paths with the star cruiser Sanctuary II piloted by the mad Titan Thanos. The Plasmagen were alarmed at the presences of Thanos, but the valiant Primo commanded his men to attack Thanos' ship, although his orders were a little late, Thanos' new underling Cap'n Reptyl, stormed into his cruiser, easily overtaking the ship and leaving Primo unconscious. Primo later woke up to see Thanos and Reptyl. Thanos presented Primo the offer of being the second member of his pantheon. Thanos absorbed the life force of Primo's crewmen and bestowed him to Godhood. Primo's first feat was the slaughter of a group of Eternals of Titan, with the help of Cap'n Reptyl. Primo, Cap'n Reptyl, and Thanos all battled the Titan and defeated the Avenger Starfox.

Primo and Reptyl's next mission was to capture Quoi the Celestial Messiah, the child of the Celestial Madonna Mantis and the Elder Cotati. Quoi was in the company of the Reptyl's former pirate and ally Raptra, their orders were to bring them both back alive. While pursuing Quoi and Raptra, Primo and Reptyl learned of the Rot, which was the offspring of Thanos and Death though they never had sexual interactions. Primo and Reptyl were able to also learn the whereabouts of Raptra and Quoi. A battle soon ensued between the two parties, resulting in Quoi and Raptra being defeated by the Pantheon of Thanos.

Later Primo looked on as Thanos jeered at Mantis, Quoi, and Raptra, who were now all his captive listeners. Primo soon began to realize the true evil of the demonic Thanos. It became apparent to him and Reptyl that Thanos sought to be the lone ruler of the universe, leaving them with nothing. Primo and Reptyl followed orders regardless of their thoughts, taking the Celestial Madonna Mantis to an operating table and strapping her down. The Avengers and the reality displaced ally Haywire came to rescue the captive heroes. Primo battled them alongside Repty and Thanos, but the battle was interrupted by the Rot, an anomalous and cosmically contradictory, concrete abstraction. Primo lost his life in the battle when the Rot simply touched him.