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Resident Evil Wiki
Prime universe
(Capcom's primary storyline)

"t" virions through a microscope.

Tyrant Virus, otherwise known as the t-Virus, is the general name given to a series of mutant Progenitor virus strains.

Initially developed by Umbrella Pharmaceuticals in the late 1960s, the primary goal of the "t-Virus Project" was to effectively eliminate the need for a large-scale conventional army and generate revenue to go to their eugenics program, the Wesker Project. This required two things: the virus had to be highly-contagious to the point of infecting an entire target population and guarantee a 100% mortality rate.[1][2] Such a virus was impossible due to such contagions' tendencies to kill too many people at once and prevent further spread.

By 1978, development moved from creating a lethal, highly-contagious virus to one that would mutate hosts to become physically stronger and remain alive despite organ failures and severe brain damage, the latter leading to murderous aggression and an obsessive hunger to the state of cannibalism.[1] With the 1981 discovery of a statistical 10% of any population being naturally immune or unmutated asymptomatic carriers,[2] Phase 2 of the research project focused on creating workarounds, and while work was under way creating an improved t-Virus with 0% immunity, the pioneering Arklay Laboratory team under Dr. William Birkin engineered a new species of animal that would hunt down and kill survivors, beginning with simple Bio-Organic Weapons such as the Web Spinner, but breaking ground with the genetically-chimeric Hunter α.[2]

In the mid-1980s, the t-Virus Project focused on creating intelligent bio-weapons, most famously the Tyrants.[3] After the collapse of Umbrella in the early 2000s, the t-Virus became available to dozens of organizations with the means to finalize Umbrella's research in their own way and dominate the weapon industry. Independently developed mutagens such as t-Abyss were developed thanks to this.


From the Progenitor Virus' discovery in December 1966, the ultimate goal of Dr. Oswell E. Spencer and his colleagues Dr. Edward Ashford and Dr. James Marcus was the birthing of a new age of eugenics with mutagenic viruses improving the human race. To fund this program, dubbed the Wesker Project, it was agreed that strains of the virus should be engineered as a military product, leading to the creation of Umbrella Pharmaceuticals as a front for this research. Research on Progenitor strains was conducted simultaneously in different laboratories, with Ashford, Marcus and Spencer all engaging in independent research. t-Virus research began in the late 1960s, soon after Umbrella was founded.[4] As the t-Virus is a series of independently developed strains and not a single virus, new strains do not necessarily rely on recent research by other teams.

Spencer project

Spencer's team developed their t-Virus prototype at the Arklay Laboratory, where they had already undergone testing of their "Type A" and "Type B" Progenitor strains. Little is known of Spencer's project, though it would appear Spencer was disappointed in its progress and ordered research data be stolen from his counterparts. Work on this virus was completely abandoned by 1978.

Ashford projects

Ashford performed research on his t-Virus prototype at his family's stately home in Europe. In 1968, Spencer orchestrated an outbreak at the lab, resulting in Ashford dying from infection. Work on t-Virus was put on hold until the 1980s, when Ashford's cousin Alexia Ashford took charge of the project. The fruit of her labours would ultimately be t-Veronica Virus, created through splicing Veronica Virus into the Progenitor genome. Alexia would go into hiding in 1983, leading to the misconception that her project was a failure and she had died just as Edward had.

Marcus-Birkin project

Dr. James Marcus' research reached a breakthrough on 13 January 1978, which warranted the official coining of the name "t-Virus" to divorce the strain from Progenitor Virus.[5][6][7] The new strain was developed by splicing annelid genes into the viral genome. Using the virus on humans saw a very different response compared with Progenitor infection, rather than dying the infected instead became aggressive, were found to have cannibalistic impulses, lost intelligence and suffered from significant necrosis.[8]

In 1978, samples and research data were stolen by Dr. William Birkin. A protégé of Marcus', he had been offered a senior position at the Arklay Laboratory on the sole condition it be delivered to Spencer's team. Immediately upon his transfer in the Summer of 1978, Birkin began drawing up plans to modify the virus further, splicing RNA from Ebola into the t-Virus' genome. This, he believed, would make the virus highly contagious while keeping most victims alive as Zombies.[1] Spencer was, however, unsatisfied with the virus the Arklay team was developing, as approximately 10% of people were determined to be unable to turn into Zombies and therefore would not aggressively spread the virus.[2] To guarantee a near 100% success rate in battle, the Arklay team bonded a human egg and reptilian DNA through the virus in 1981, creating the "Hunter," a creature that would be used in battle to kill these remaining survivors.[9] Because the t-Virus can make genetic recombination between different species comparatively easy, this virus was mass-produced within Umbrella and supplied to each research facility for new B.O.W. model development.[10]

Starting around 1988, development of the t-Virus entered Phase 3 with the intention of creating reliable, intelligent B.O.W.s. Its counterpart Tyrant Project had at the time determined it was statistically improbable for any one individual to possess by chance the genetic characteristics to be compatible with the t-Virus strains presently available. For the next several years, the Arklay Laboratory and NEST led global research into the ε strain. This new virus was also discovered in 1998 to force a second set of mutations in Zombies, resulting in creatures such as Crimson Heads and Lickers.

Later research

New viral strains were developed towards the end of Umbrella's existence and the years following. One such version was the t+G-Virus, a t-Virus strain which was able to enhance infected bodies with the ability to discharge electricity. t-Abyss was created under the oversight of Morgan Lansdale, which grafted the genome of another virus onto a t-Virus strain. t-Phobos was engineered by Dr. Alex Wesker to trigger mutations in humans when it came into contact with certain levels of stress hormones indicative of fear. C-Virus was a heavily re-engineered strain of t+Veronica used by Neo-Umbrella in 2012 for bioterror purposes.


Effects of Infection

Like any other viruses, t-Viruses make contact with a cell's membrane and insert their genetic coding into the cell. The cell absorbs the viral genome into its own, which hijacks the cell's intended functions, using them to produce virions similar to the original. The new virions are then released from the host cell and infect the neighboring cells, which starts the process all over again.[11]

Several diseases have been linked to t-Virus. The first, which can be tentatively dubbed as "Progenitor disease", is a fatal viral disease caused by Progenitor and early t-Virus strains. Nothing is known concretely about how this disease works, whether causing a cytokine storm or simply rapidly mutating the patient until they die. The most common disease caused by t-Viruses however is Cannibal Disease, a condition in which the patient mutates to have enhanced survival capabilities at the expense of brain damage and homicidal urges. Patients suffering advanced-stage Cannibal Disease are dubbed "Zombies", with pre-symptomatic and early-symptomatic cases being treatable with antiretroviral drugs. In ε strain and its variants, Zombies also undergo a variety of mutations over time, such as Crimson Heads, Lickers, the Suspended and Pale Heads.

An unusual case of viral infection occurs in the bodies of adaptors, wherein they gain superhuman abilities with limited to no brain damage. As the genetic criteria for this unique reaction was rare (a 1988 estimate put it at 1 in 10 million), no such human mutants are known to have existed until the 1990s with the Tyrant Project's initial prototype B.O.W.s. A number of other people such as Sergei Vladimir and Albert Wesker gained enhanced superhuman abilities following their own t-Virus infections, though these were specially engineered t-Virus strains designed to near-guarantee such mutations.

Means of infection

The t-Virus is capable of various methods of subject infection. Research files supplied in the Arklay Laboratory identify the virus as having a protein structure.

  • Injection: Due to its importance in bio-weapons development, the direct injection of the virus into an organism's body was considered by Umbrella to be the "primary" means of infection.
  • Water: Raccoon Dam and the Raccoon Sewage Treatment Plant were contaminated with the virus, leaking into the city's water supply as a result and infecting many civilians.
  • Direct Fluidic Transmission: Anyone attacked by an infected host in close combat, be it by bite, scratch, gash, or stab may have the virus transferred to their bloodstream via contact with infected bodily fluids and tissues. Umbrella Corp. believes this to be a secondary means of infection. It is not a precise form of infection, however, as dry bites are a possibility.
  • Airborne: Evidence in the Arklay Laboratory and the Military Training Center indicates the t-Virus is capable of spreading as an airborne pathogen in unspecified laboratory conditions. Whether or not it can spread between individuals through coughing is uncertain, as coughing fits do not appear to be a common symptom.

Known treatments

A number of treatments are known to exist for t-Virus infection, developed either internally by Umbrella or by third-party groups. There are overall three distinct types of treatment for the virus: antiretroviral therapy (ART), antibody therapy, and vaccination. It should be noted that no treatment is expected to work with all strains of the virus.

In the 1990s, Umbrella was mass-producing antiretroviral drugs for internal use, and were supplied to those in high-risk professions. These drugs inhibit the production of certain enzymes required for the replication of retroviruses. Research on this front was continuous, with one study aimed at the effectivity of antiviral drugs made from herbs growing in the Arklay Mountains, something that was continued by third parties.[12] In outbreak situations, these drugs had mixed results and could not be guaranteed to work on novel t-Viruses where the chances of drug-resistant strains was high. During Raccoon City, for example, UBCS mercenaries were provided with drugs to ward off infection, though at least one mercenary - Murphy Seeker - was infected with a drug-resistant strain and had to be euthanised. Sgt. Nikolai Zinoviev, a mercenary with ties to Umbrella's secret police, was provided with a more advanced version of these same drugs to lower the chances of infection.

A second form of treatment used by Umbrella was antibody therapy, wherein antibodies from one patient are implanted within another to provide resistance. These antibodies were provided in tablet form for high-risk workers, among whom those assigned to Incineration Disposal Plant P-12A. It was, however, ineffective during the July 1998 outbreak at this factory, when a novel t-Virus spread amongst the workers which was resistant to the prescribed antibodies. As consequence, the workers succumbed to Cannibal Disease.[13] An example of an independently developed antibody therapy is Daylight, which was developed by Dr. Peter Jenkins in 1998.[14] A sample of this treatment was successfully taken out of the city, and became a recommended treatment for people recently exposed to the virus.[15] Similarly, a team at the Umbrella R&D Center developed AT1521; through all samples were destroyed, one of its creators Dr. Linda Baldwin was successfully evacuated.[16]

At least two vaccines are also known to have been developed for t-Virus, which had a degree of effectivity when administered to the recently infected. While Umbrella itself likely had its own vaccine supplies, the earliest known vaccine to exist was an independently-made vaccine created in Raccoon City by surviving medical personnel at Raccoon General Hospital. All samples of the vaccine as well as the research data were destroyed due both to the destruction of Raccoon City itself and attempts by Umbrella to destroy evidence. S.T.A.R.S. officer Jill Valentine was treated with this vaccine.[17] A second vaccine was developed by the WP Corporation in 2005 in partnership with the Pentagon. Dubbed merely the t-Vaccine, it represented the US' commitments to nullifying the threat posed by the t-Virus. Though it had a successful trial in both India and the American city of Harvardville, a terrorist bombing of the laboratory complex destroyed the research data and all but one sample.[18]



  1. 1.0 1.1 1.2 Wesker's Report II, Chapter 1.
  2. 2.0 2.1 2.2 2.3 Wesker's Report II, Chapter 2.
  3. Wesker's Report II, Chapter 4.
  4. Resident Evil CODE:Veronica (2000), file: "Alexander's Memo"
  5. Resident Evil Archives, page 266
  6. Resident Evil 0 (2002), file: "Leech Growth Records"
  7. Resident Evil 5, file "Telegram from James Marcus"
  8. Resident Evil 5 (2009), file: "History of RESIDENT EVIL"
  9. Wesker's Report II.
  11. Wikipedia: Viral Replication at Wikipedia
  12. Resident Evil: Revelations (2012), file: "Botany Plants with Medicinal Properties - 3rd Edition"
  13. Resident Evil 3: Nemesis (1999), file: "Manager's Diary".
  14. Resident Evil Outbreak (2003), file: "Peter's Diary".
  15. Resident Evil: The Marhawa Desire, issue 1: "Academy of Tragedy".
  16. Resident Evil Outbreak File #2, "end of the road"
  17. Resident Evil 3: Nemesis
  18. Resident Evil: Degeneration.