(Capcom's primary storyline)
NE-α (Nemesis alpha), was an artificially-engineered species of parasitic organism created by Umbrella Europe. It was created to increase the intelligence and ability to follow orders of selected B.O.W.s. The NE-α affects the compatible host's brain, taking it over and enhancing intelligence and susceptibility to suggestion. If the parasite has an incompatible host, the host will die within a matter of minutes.
Nemesis was developed by Umbrella Europe in 1988 through gene manipulation. Developing several of these parasites, one sample was sent to the Arklay Laboratory on the request of Albert Wesker and the approval of Oswell E. Spencer. The two teams were planned to develop on two aspects of the bioweapons program; the Arklay team studied into combat-effectiveness, while the Parisian team researched into intelligence - they would then merge their studies together to form a single bio-weapon. The highly-intelligent parasite was developed with the capability of taking control over its host by fusing with its brain. A major problem occurred in the process, however - all hosts died within five minutes of coupling. All, that is, until the Arklay team's experiment.
Wesker knew of the constant deaths the parasite had caused, but also knew a way around it - Lisa Trevor. Lisa, who had been used as a guinea pig for the Arklay team's experiments for nineteen years, had developed a primitive strain of what William Birkin would later call "G-virus". Inserting the parasite into the woman's brain, the team, especially Albert, were astonished to find that it simply disappeared, absorbed into her body.
Much later, in 1998, the Arklay facility suffered a viral outbreak in which the entire research staff (except Wesker) were killed or infected by the t-Virus. An investigation of the facility's mansion façade by the Raccoon City Police Department's Special Tactics And Rescue Service led to their discovery of the T-002, a fully-developed and combat-ready Tyrant. While it was killed by the S.T.A.R.S. officers, Umbrella got their hands on the combat data required to ascertain its effectiveness.
Shortly afterwards, Umbrella Europe began to partner at least 4 Nemesis parasites with the newly created T-103 series, which were designed based on the same acquired data. The outcome of this development was Nemesis-T Type.
It is unknown if Umbrella made other experiments with the parasite.
- The NE-α Type Parasite's tentacles resemble the tentacles seen around the body of the Nemesis-T Type, which also has the ability to use them as a weapon. This suggests that the parasite is capable of extending its appendages from its host's flesh at the host's mental command for use in combat.
- Lisa Trevor was the first patient to survive the parasite, though her body simply absorbed it.
- It is unknown if the parasite was successfully used on any other host or B.O.W. aside from the Nemesis T-Type.
- Resident Evil: Operation Raccoon City, which exists in a separate universe, has work on the NE-α Type continue, resulting in the NE-β Type.