The G-virus was developed by
Umbrella Corporation scientist
William Birkin, who had also taken James Marcus's work on the
T-virus.
A primitive form of the virus was discovered in the mutated body of
Lisa Trevor, on whom the Umbrella Corporation had been conducting unethical genetic and viral experiments for three decades. When she displayed unexpected immune resistance to the experimental
NE-Alpha parasite, Birkin and other researchers looked for a cause and found what would later become the G-virus.
The G-virus, shown as a purple, aqueous
liquid in a glass vial, greatly increases the host's metabolism, which accelerates cellular duplication and revitalization of dead cells. However, the continual destruction of mitochondria in the host's neurons causes an infected person to degrade to sub-human levels. The host exhibits animalistic behavior, loss of moral reasoning and memory, and becomes driven by self-preservation. Ultimately, carriers become creatures simply dubbed
G.
Beyond these qualities, the mutations induced by the virus tend to be extremely volatile. The only known hosts were
William Birkin, his daughter
Sherry,
Curtis Miller and
Dexter Whitlam. William injected himself with the virus after being mortally wounded by an
Umbrella Security Service unit attempting to recover the G-virus from his labs. Unlike
T-virus hosts, G-virus hosts never stop mutating, even without external stimuli, thus causing transformations akin to a sort of artificial evolution, accelerated to levels impossible to be recreated in nature. G-Carriers evolve even faster when wounded, due to the incredible regenerative capabilities of infected cells. Curtis injected himself to denounce the "atrocities" by the WilPharma company, which, in its quest to create a viable "t" vaccine, had apparently infected countless people to use as guinea pigs. Sherry was infected by William. As their DNA matched, she was destined to become like him. The mutations were stopped before beginning.