The following Powermaster toys were released in the United States and Canada: Autobots
Transformers had previously visited Nebulos and bonded with its inhabitants during the creation of the Headmasters and Targetmasters, caused severe devastation to the world and the loss of two of its most noted political leaders. To ensure that the planet would never come under threat from Transformers again, Nebulan scientist Hi-Q detonated a bomb that filled the planet's atmosphere with radiation that posed no threat to indigenous Nebulan life, but which "poisoned" Nebulan fuel supplies, making it harmful to Transformers. Not long after, the Decepticons Dreadwind and Darkwing arrived on the planet looking for the absent Scorponok, and, despite warnings, consumed Nebulan fuel. Their bodies wasted and they were rendered immobile, becoming something of a tourist attraction over time.
Hi-Q's jealous ex-partner, Hi-Test, sought to discredit his former colleague, and teamed up with a Nebulan criminal named Throttle, who stole data on Hi-Q's latest fuel conversion theories, which he had dubbed the "Powermaster Process". Using the data, Hi-Test bio-mechanically engineered his and Throttle's bodies, allowing them to transform into engines and connect to Dreadwind and Darkwing, supplying them energy directly from their own bodies.
As the Decepticon Powermasters ran roughshod over the planet, the Autobot Goldbug arrived from Earth with Getaway, Joyride and Slapdash, hoping that Nebulan science could build a new body to house the mind of Optimus Prime. When the Autobots refused to leave the planet even after being warned about the poisoned fuel, Hi-Q agreed to construct Prime's new body, while the Autobots drained their energy fending off an attack by the Decepticons. Prime's mind was placed within his new body, but he immediately began to die due to the Nebulan fuel that powered it. Realising the nobility and humanity of the Autobots, Hi-Q agreed to save Prime's life by merging with him as a Powermaster, while his assistants, Rev, Hotwire and Lube bonded to Getaway, Joyride and Slapdash to save them. Dreadwind and Darkwing were defeated by the new Powermasters and exiled from Nebulos, while the Autobots left to rejoin their fellows on Earth.
The ultimate, unintended extension of the Powermaster process later became apparent when Optimus Prime began to suffer seizures and bursts of pain. During the climactic battle with Unicron, he separated from Hi-Q and sacrificed himself to destroy the Chaos-Bringer, but Hi-Q soon realised that the seizures had been the forerunner of an incredible metamorphosis - the complete bonding, both mental and physical, of himself and Optimus Prime into a singular being. With Prime's body destroyed, this merging finished itself solely within Hi-Q's body, accelerated to completion by his exposure to Nucleon. The singular intellect within Hi-Q's body considered itself to be Optimus Prime, and he led the Neo-Knights on a mission to the depths of Cybertron to locate the Last Autobot, who disassembled and reconfigured Hi-Q's body into a new form for Optimus Prime.
Years before the beginning of the series, the evil alien energy entity and self-styled "Decepticon God", Devil Z, stole the eight Transtectors from the sector of space known as the G Nebula, rich in Techokon (the power of the Heavens) and sent them to Earth, intending for them to lay in hiding on the planet, gradually soaking up Chichokon (the power of the Earth). The final stage of his plan was to revive the Transtectors as a new breed of lifeform by merging them with human beings, thereby adding Jinchokon (the power of Man) to the equation, giving the resultant "Godmasters" the power to manipulate the three primal energies of the universe. As they plummeted towards the planet, the seven smaller fragments broke off from the largest body and crashed in various places across the world, while the largest body buried itself in an underwater trench.
Some of the Transtectors adopted vehicular disguises to hide in plain sight - such, at least, was the case with the one which was intended to be used as a body for Optimus Prime, which, through coincidence or design, became a tractor-trailer. At least two of the Transtectors did not adopt forms, remaining shapeless lumps of black matter, buried in the Canadian Rocky Mountains - one of them was mined as ore and used in the construction of British Motors' signature car, while the other was eventually found by Ranger and kept by him for simple artistic appreciation. The largest of the Transtectors was uncovered by Giga and Mega, who came to serve Devil Z and located two further Transtectors for Buster and Hydra.
When a young truck driver named Ginrai rented the Transtector truck from the garage owner who possessed it, he discovered a set of Master-Braces - the metallic bracelets which endow humans with the Masterforce - within it, merging with the Transtector to become the first Autobot Godmaster. His Transtector later activated on its own, locating its' secondary portion buried beneath a mountain in Japan, which took the form of a trailer to go along with the cab, allowing Ginrai to merge the two sections together to become Super Ginrai.
Subsequently, the race began to locate the remaining Godmasters, which Ginrai kicked off by appearing on television to appeal to individuals for a lead. When Lightfoot contacted him, Ginrai soon helped his discover that British Motors' signature car, which his father had constructed and gifted to him, was his Transtector. Investigating the Rockies at Lightfoot's suggestion, the Autobots met with Ranger; when he was given Master-Braces, his Transtector took the form of a dune buggy. The fourth Autobot Godmaster was racing champ, Road King, whose race car was his Transtector, which had been given to him by his mentor. The final Godmaster, Doubleclouder, did not appear for some time afterward, but no explanation for how he discovered the final Transtector was offered.
At the conclusion of the series, Buster and Hydra, seeking to discard the humanity that they believe makes them weak, are permanently fused with their Transtectors, becoming wholly robotic beings. Giga, Mega and Clouder are forcibly separated from their Transtectors by Devil Z, who brings the Transtectors to life himself. When Devil Z is successfully destroyed by God Ginrai, the Autobots Godmasters are all also separated from their Transtectors, who have, through their partnership with their human components, evolved into fully-fledged Transformer lifeforms, and depart Earth to join the greater battle in space.