Chemical A0-3959X.91 – 15 (Earth-9471)

"The pathogen is protean, changing from liquid to airborne to blood transmission, depending on its environment. It's almost impossible to kill."

- - Red Queen

Chemical A0-3959X.91 – 15, also known as Agent A0-3959X.91 – 15, "black liquid", or "Purity", is a strong and potent virulent mutagenic pathogen which consists of millions of micro-organisms. The chemical was manufactured by the ancient forerunner species as a bio organic weapon (B.O.W.) for unknown reasons, which they stored within steatite ampules.

History
The chemical was created by the forerunners at approximately 100,000 BCE on the moon of LV-223 for reasons unknown, but presumably to wipe out the life of entire planets. For reasons unknown, the forerunners were exposed to the pathogen, seemingly extinguishing the entire species with the exception of a lone individual in cryosleep.

In 2393, the USCSS Prometheus arrived on LV-223 to locate forerunners following the discovery of ancient cave drawings on the Isle of Skye, on Scotland. Some of the crew members were exposed to the chemical and became infected, killing those who were not. The few survivors sacrificed their own lives, as well as the Prometheus, to destroy a Juggernaut, while Dr. Elizabeth Shaw and the Replicant David boarded another Juggernaut-class vessel in the search of the Paradise, seemingly the homeworld of the forerunners.

The surviving forerunner was later impregnated by a Tribolite, leading to the birth of athe Deacon. In the aftermath of the disastrous expedition, which included the death of the Umbrella Corporation's founder, Peter Bishop, the Umbrella Corporation hid all the information regarding the discoveries made on LV-223, and later uncovered a manual retrieved by an U.S.S. team which concerned the workings of the chemical, the glyphs which were all translated by one of the company's Replicants. The discovery of the document led to the attempted manipulation and weaponization of the chemical as a bio organic weapon by the Umbrella Corporation under Dr. Charles Ashford and Dr. Michael Bishop from 2492 to 2552, who took over the project in the hopes that the groundbreaking scientific discovery would reverse the degenerative illness of his daughter, Angela "Newt" Ashford. His research was primarly conducted at the Hive, a massive underground facility underneath New York City.