GoBots was a line of transforming robot toys produced by Tonka from 1983 to 1987, similar to Transformers. Although initially a separate and competing franchise, Tonka's Gobots became the intellectual property of Hasbro after their buyout of Tonka in 1991. Subsequently, the universe depicted in the animated series Challenge of the GoBots and follow-up film GoBots: Battle of the Rock Lords was established as an alternate universe within the Transformers franchise. While Hasbro now owns the fictional side of the property (character names, bios, storyline), the actual toys and their likenesses were only licensed from Bandai in the 1980s, were not covered by the Tonka acquisition, and are not available for Hasbro use.
The GoBots were originally an organic race known as "GoBings" and were similar to humans. They resided on the planet Gobotron which was ruled by the benevolent Guardians for thousands of years until a terrible civil war broke out. A terrorist faction known as the Renegades made a bid for domination of the planet, waging a destructive campaign that brought the GoBings to the brink of extinction. However, the genius who became known as the "Last Engineer" saved his people, taking his experiments to replace parts of his own body with mechanical substitutes to the ultimate extent and transferring the GoBings brains into large robot bodies known as "GoBots".
The GoBot forms possessed an additional ability; after being run through the device named the Modifier, the GoBots' bodies were able to transform into other vehicles. His work done, the Last Engineer intended to retreat to a pre-prepared workshop elsewhere in the galaxy, but the Master Renegade stole his ship and escaped in his stead. The Last Engineer placed himself into suspended animation beneath the surface of Gobotron, while above, the war continued to rage between the Guardians and the Renegades, now all encased in GoBot shells.
In the last quarter of the 20th Century, the planet Earth became involved in the conflict between Leader-1's Guardians and Cy-Kill's Renegades. During one of these battles, one of Leader-1's lieutenants, Turbo, became severely damaged. Unwilling to let his friend and teammate die, Leader-1 began his quest to find the legendary Last Engineer. Leader-1 found the person he believed to be the Last Engineer, but Leader-1 had unwittingly released the Master Renegade (though he did repair Turbo to gain the Guardians' trust).
The Guardians later found the true Last Engineer, who was instrumental in frustrating the alliance between Cy-Kill's Renegades and the Master Renegade. The Master Renegade later escaped the custody of the Renegades, and plagued both factions, notably attacking the UniCom colony of New Earth.