The Progenitor Virus was a double stranded RNA virus originating in ancient Western Africa, which was the basis of the bioterrorist agent known as the T-Virus. Originally highly potent poisonous plants that were central in the culture of the Ndipaya tribe, and the flowers were harvested by Umbrella to extract the Progenitor virus.
A breed of flowers called "Stairway of the Sun", was first discovered by Westerners in the 19th century, and the virus that was extracted from it would become the base from which the Umbrella Corporation's most successful Bio Organic Weapons research would ever stem several decades later.
Derived from the "Stairway of the Sun" flower, it was rediscovered in the Kijuju region of West Africa on December 4, 1966 by Lord Oswell E. Spencer; Dr. James Marcus and his student Brandon Bailey, after three months of searching, in an attempt to prove the validity of Henry Travis, a man who mentioned the flower over a century previous and was promtly discredited. Naming the virus within it "Progenitor", Dr. Marcus made preparations to leave Africa with a sample to begin his research immediately.
Unfortunately for Marcus, the mass-cultivated flowers were found to not produce the virus and it was concluded by Bailey that local environmental factors were necessary for its cultivation.
Umbrella's Progenitor Research
Despite months of cultivations using varying factors (different soil; temperature; water and light-exposure), the trigger for the virus' production could not be found. Despite the lack of any real development, Spencer began making plans to set up a company in March 1967; while Bailey saw it as pointless without any progression with the virus, Marcus went along with it for as long as it didn't interfere with his research.
In November, Spencer began to show his true colours. After his private mansion in the Arklay Mountains was built to hide his Laboratory, he had the building's architect, George Trevor; his wife Jessica and daughter Lisa used as part of his research into the Progenitor virus. Only Lisa survived.
A number of events, both good and bad, occured in 1968: firstly, the African expedition began to push the Ndipaya out of their ancient, ruined city in order to locate the Sun Garden. In July, Umbrella co-founder Edward Ashford became the first Westerner to perish from exposure to the virus. The next month, with the Sun Garden secured, Marcus and Bailey set up a research station within the cave before Marcus was called-up by Spencer to administrate the Umbrella Research Center, where Spencer continued to investigate and study the virus. With the African outpost established in September of that year, Dr. Bailey began exporting newly-cultivated samples straight to Marcus.
Birth of Tyrant
In the January of 1978, James Marcus combined the Progenitor virus with leech DNA, creating the Tyrant virus. In 1988, Dr. Marcus' two most valued (and, ironically, most trusted) assistants, William Birkin and Albert Wesker, would then assassinate Marcus at the order of his partner and fellow co-founder, Lord Spencer. The two would continue his research from within the secluded Arklay Laboratory. Here, under Spencer's supervision, Dr. Birkin continued to experiment on Lisa; these experiments led to the creation of the G-virus at a much later point in time, discovered by mixing the Type-B Progenitor virus and the countless viral experiments made on Lisa and the NE-α Type parasite, injected into her body.
Path to Godhood
In 2006, Lord Spencer in his waning years, met with Albert Wesker to discuss his plans for world domination through Umbrella's rebirth. Having grown arrogant as leader of the now disestablished corporation and his knowledge of B.O.W.s, Spencer felt it was his right - and only his right - to become a god among men. In his hubris, Spencer revealed that Wesker was the product of an experimental hybridization between humans and the Progenitor virus. There were multiple "Wesker Children", children of intellectuals, hand picked and programmed with Spencer's values, but only two, Albert Wesker and Alex Wesker survived and flourished. Upon discovering this, Wesker brutally murdered the decrepit president of Umbrella, and decided to use the power of Progenitor for his own gain by using it in the development of the powerful virus known as "Uroboros".
There are at least two strains of the Progenitor Virus:
The Type-A strain was tested on Jessica Trevor on November 10, 1967. The virus failed to fuse with her DNA and she was later killed. It should be noted that she did not simply die from Progenitor, which were the fates of Marcus' human "test-subjects". Furthermore, she managed to live for three days, and with a reasonably good-condition brain. Her mind was not fully intact, however, describing drifting into unconciousness and memory loss in a letter.
The Type-B strain was tested on Jessica's daughter, Lisa on the same day. This strain of the virus succeeded in fusing with her DNA, albeit with a delayed reaction. Her brain - either due to the virus strain or her young age of 12 - was significantly affected by the virus, killing an imposter impersonating her mother five days later and losing the ability to write by November 17. By December 4, all she can write was "I mis yuo".
- In an earlier development version of Resident Evil 4, Leon was to be infected with the Progenitor virus, encountering bizarre apparitions as part of his infection. One of these such apparitions was noticably similar to the worm-like creations of the Uroboros Virus.
- Early on in the series, the Progenitor Virus itself was also known as the "Clay Virus", with the T-Virus being the "E-type".