(King's BIO HAZARD2 mythos)
The G-Virus (G——细菌, though also referred to simply as "G菌") is a virus possessing supernatural abilities. It was the produce of an ancient civilisation, which the Umbrella Group redeveloped as prophecised.
Umbrella's G-Virus was developed by Dr. William, who infected himself when Umbrella tried to steal the work. The virus typically caused people to act violently and give in to emotional and sexual urges, as seen by the "G Zombies" on the artificial island.
Sherry Birkin was also infected with the virus, but because she was a Patron Saint, she was immune to its negative effects. She was able to control zombies, keeping them away from her and Claire in Raccoon City. When she rapidly aged into a grown woman, she demonstrated the ability to heal wounds by touch, doing so to an injured man's leg at the B.H.S.T. base.
Both King's Foundation and Tinhangse refer to the G-Virus in Hanzi repeatedly as "G菌", suggesting a bacteria.