The Cyborgs are former Terrans who have undergone major genetic mutations, allowing their bodies to accept large numbers of artificial implants, breaching the barrier between man and machine.
The Cyborgs have since been limited to very small numbers and have been expelled from Terran society. A few that survived the great destruction of Gaia have recently appeared in Terran space offering help against the deadly Biomass.
The Terrans depended on Cyborgs to act as the supreme defenders of ancient Gaia. A number of systemic abuses, tensions and differences between Cyborgs and regular Terrans led to the ancient Cyborg Revolution. When the rebellion took place, the Cyborgs easily took control of all technology in Terran space. The eventual defeat of the Cyborgs by the Terrans led to a complete ban of implants and artificial intelligence.