4. Gray Death – Deus Ex
The Gray Death was manufactured using nanotechnology by an organization known as Majestic-12. A hybrid (cyborganic) disease of biological and mechanical structure, the virus is based on the lethal effects of implementing nanotechnology to an unmodified human body that then rejects the mechanical elements of the virus.
Its creation was devised to rid the already overpopulated world of its poorer inhabitants and provide a vaccine in limited quantities to only those able to pay for treatment.