Earth 43

Earth 43's history differed from Earth 2's history when a commercial ship escaped pirates in 2192. On that ship, an eight year old child, who died on Earth 2, survived scientist and grew up to be the outlaw scientist Dr. Ishmael Mantel. 
Dr. Mantel created a self-replicating metal entity in the hopes of discovering a way to better integrate people with prosthetics, so they could function about the same as a natural limb could. Unfortunately, this went horribly wrong when the entity bonded with the scientist, incorporating his body bit-by-bit until he was a metal man. He was the first of the Cyber, a race of merciless robots, that wish to turn all humans into figures like them. The Cyber inject one of their viral cells into the bloodstream of their victims, and the viral cell will spread through the body, converting cell after cell into metal Cyber-cells. The last thing to be converted in all cases, is the human's brain, which by that point would have no power over its body. The brain is slowly converted into a robot, slave to the Cyber's collective mind, with the human's memories and experience added to the whole...whether the human wanted to or not. 
The humans and Cybers of this planet fight an extinction war, both fighting to continue their existence, each race an existential threat to the other.