1. This virus is far more powerful than the T-virus and was developed by a researcher named William Birkin. The T-virus only causes one generation of mutations, but the G-virus can continue beyond one generation. When the Nemesis prototype was used on the test subject Lisa Trevor, her body served as the source of the original G-virus’s discovery.
2. William injected himself with the G-virus and transformed into this monster. This monster is also called “G”, but to help distinguish its name from the virus, the monster is sometimes called “Birkin G”. This monster underwent extreme mutations until eventually reaching a fifth form, when it was finally destroyed by Leon and Claire in the research facility under Raccoon City.