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Prime universe
(Capcom's primary storyline)
For other uses, see T-Virus (disambiguation).

Tyrant Virus, also 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 for 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] However, such a virus was deemed impossible due to the tendency of highly contagious diseases to kill too many people at once and prevent further spread.

By 1978, the development focus shifted 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 led to murderous aggression and an obsessive hunger that drove individuals to cannibalism.[1] Additionally, with the discovery in 1981 that approximately 10% of any population was naturally immune or unmutated asymptomatic carriers,[2] Phase 2 of the research project aimed at finding workarounds. While an improved t-Virus with 0% immunity was being developed, the Arklay Laboratory team, led by Dr. William Birkin, engineered a new species of animal that could hunt down and kill survivors. This effort began with the creation of simple Bio-Organic Weapons such as the Web Spinner and progressed with the development of the genetically chimeric Hunter α.[2]

In the mid-1980s, the t-Virus Project shifted its focus to the creation of intelligent bio-weapons, most notably the Tyrants.[3] Following the collapse of Umbrella in the early 2000s, the t-Virus became accessible to numerous organizations capable of finalizing Umbrella's research in their own ways and dominating the weapon industry. This led to the independent development of mutagens like t-Abyss.


From the discovery of the Progenitor Virus in December 1966, the ultimate goal of Dr. Oswell E. Spencer and his colleagues, Dr. Edward Ashford and Dr. James Marcus, was to usher in a new age of eugenics by using mutagenic viruses to improve the human race. To fund this program, known as the Wesker Project, they decided to engineer virus strains as military products, leading to the establishment of Umbrella Pharmaceuticals as a front for their research. Research on Progenitor strains was conducted simultaneously in various laboratories, with Ashford, Marcus, and Spencer each pursuing independent research. t-Virus research began in the late 1960s, shortly after the founding of Umbrella.[4] As the t-Virus comprises a series of independently developed strains rather than a single virus, new strains do not necessarily rely on recent research conducted by other teams.

Spencer Project[]

Spencer's team developed their t-Virus prototype at the Arklay Laboratory, where they had previously tested their "Type A" and "Type B" Progenitor strains. Limited information is available about Spencer's project, but it appears that Spencer was dissatisfied with its progress and ordered the theft of research data from his counterparts. By 1978, work on this virus had been completely abandoned.

Ashford Projects[]

Edward Ashford conducted research on his t-Virus prototype at his family's estate in Europe. In 1968, Spencer orchestrated an outbreak at the laboratory, resulting in Ashford's death from infection. Work on the t-Virus was put on hold until the 1980s when Alexia Ashford, a genetically modified clone of Veronica Ashford, the founder of the Ashford family, took charge of the project around the age of ten. The culmination of her efforts would eventually result in the creation of the t-Veronica Virus. This was achieved by splicing the Veronica Virus, a virus found inside a queen ant, into the Progenitor genome. In 1983, Alexia went into cryogenic suspension to become one with her virus, leading many who did not know this fact to believe that her project had failed and that she had perished like Edward.

Marcus-Birkin Project[]

Dr. James Marcus' research led to a breakthrough on January 13, 1978, which prompted the adoption of the name "t-Virus" to distinguish it from the Progenitor Virus.[5][6][7] The new strain was developed by introducing annelid genes into the viral genome. Infection with this virus yielded a different response compared to Progenitor infection: instead of succumbing to death, the infected individuals became aggressive, developed cannibalistic tendencies, suffered severe necrosis, and experienced a significant decline in intelligence.[8]

In 1978, Dr. William Birkin stole samples and research data. Birkin, a protege of Marcus, was offered a senior position at the Arklay Laboratory on the condition that he deliver the research to Spencer's team. After his transfer in the summer of 1978, Birkin began modifying the virus by splicing RNA from Ebola into the t-Virus' genome, creating the β strain. He believed that this modification would increase the virus's contagion while still allowing most victims to remain alive as zombies.[1]

However, Spencer was dissatisfied with the virus developed by the Arklay team, as approximately 10% of the population naturally possessed immunity to the virus, rendering them unable to turn into zombies, although they could still act as carriers.[2] To ensure a near 100% success rate in battle, the Arklay team created the "Hunter" in 1981 by fusing human eggs and reptilian DNA through the virus. These creatures were deployed in combat to eliminate any remaining survivors.[9] The t-Virus facilitated genetic recombination between different species, making it easier to produce the virus on a large scale within Umbrella and supply it to various research facilities for the development of new Bio-Organic Weapons (B.O.W.s) models.[10]

Around 1988, the t-Virus entered Phase 3 with the aim of creating reliable, intelligent B.O.W.s. The Tyrant Project concluded that it was statistically improbable for any individual to possess the genetic characteristics necessary to be compatible with the t-Virus strains available at the time. For several years, the Arklay Laboratory and NEST conducted global research on the ε strain. This new virus was discovered in 1998 to induce a second set of mutations in zombies, resulting in the creation of creatures such as Crimson Heads and Lickers.

Later research[]

New viral strains were developed toward the end of Umbrella's existence and in the years that followed. One of these strains was the t+G-Virus, derived from the t-Virus, which enabled infected bodies to generate electricity. Another variant, t-Abyss, was created under the supervision of Morgan Lansdale by grafting the genome of another virus onto a t-Virus strain. Dr. Alex Wesker engineered t-Phobos to induce mutations in humans upon contact with stress hormones associated with fear. The C-Virus, utilized by Neo-Umbrella in 2012 for bioterrorism purposes, was a heavily re-engineered version of the t-Veronica strain.

A new t-Virus strain was developed by Dylan Blake specifically to "clean the slate" of society which enhanced using Arias' A-Virus and harvested from Licker Larva. The vectors of this t-Virus strain were experimental mosquito drones (programmable bioweapons enhanced with military-grade robotics) created with reluctant aid of Dr. Antonio Taylor which would infect individual targets. Unlike its predecessor however, it was non-transmissible and therefore the infected could be euthanized without causing an outbreak.[11]


Effects of Infection[]

Like any other Retrovirus, t-Viruses make contact with a cell's membrane, using a process called Reverse Transcription the virus can copy its RNA and insert it into its hosts DNA. This rewriting of DNA hijacks a cells intended functions and uses them to produce virions similar to the original virus. The newly formed virions are then released from the host cell and infect neighboring cells, initiating the process once again.[12]

Several diseases have been associated with t-Virus infection. The first, tentatively referred to as "Progenitor disease," is a fatal viral illness caused by Progenitor and early t-Virus strains. The exact mechanism of this disease is unknown, including whether it triggers a cytokine storm or rapidly mutates the patient until death. However, the most common disease caused by t-Viruses is Cannibal Disease, a condition in which patients mutate to gain enhanced survival capabilities at the cost of brain damage and homicidal urges. Advanced-stage Cannibal Disease patients are referred to as "Zombies," while pre-symptomatic and early-symptomatic cases can be treated with antiretroviral drugs. In the ε strain and its variants, Zombies undergo various mutations over time, such as becoming Crimson Heads, Lickers, the Suspended, or Pale Heads.

An exceptional case of viral infection occurs in adaptors, individuals who acquire superhuman abilities with minimal to no brain damage. As the genetic criteria for this unique reaction are rare (estimated at 1 in 10 million in 1988), no such human mutants were known to exist until the 1990s when the Tyrant Project's initial prototype B.O.W.s were created. Other individuals, such as Sergei Vladimir and Albert Wesker, gained enhanced superhuman abilities following their own t-Virus infections. However, in these cases, specially engineered t-Virus strains were used to increase the likelihood of such mutations, and Sergei Vladimir already had genetic compatibility with the virus.

Means of Infection[]

The t-Virus is capable of infecting subjects through various methods. Research files from the Arklay Laboratory indicate that the virus has a protein structure.

  • Injection: Direct injection of the virus into an organism's body was considered the "primary" means of infection due to its significance in bio-weapons development.
  • Water: The t-Virus contaminated Raccoon Dam and the Raccoon Sewage Treatment Plant, leading to its leakage into the city's water supply and infecting many civilians.
  • Direct Fluidic Transmission: Close combat attacks by infected hosts, such as bites, scratches, gashes, or stabs, can transfer the virus to the bloodstream through contact with infected bodily fluids and tissues. Umbrella Corporation considers this a secondary means of infection. However, precise infection through dry bites is uncertain.
  • Airborne: Evidence from the Arklay Laboratory and the Military Training Center suggests that the t-Virus can spread as an airborne pathogen under specific laboratory conditions. It is unclear whether it can be transmitted between individuals through coughing, as coughing fits do not appear to be a common symptom.

Known Treatments[]

Several treatments are known to exist for t-Virus infection, developed either by Umbrella internally or by third-party groups. There are three distinct types of treatment for the virus: antiretroviral therapy (ART), antibody therapy, and vaccination. It is important to note that no treatment is expected to be effective against all strains of the virus.

In the 1990s, Umbrella mass-produced antiretroviral drugs for internal use and supplied them to individuals in high-risk professions. These drugs inhibit the production of specific enzymes necessary for retrovirus replication. Ongoing research explored the effectiveness of antiviral drugs derived from herbs in the Arklay Mountains, study that was also pursued by third-party entities.[13] In outbreak situations, the results of these drugs varied and could not be guaranteed to work against new t-Viruses, as the likelihood of drug-resistant strains was high. For example, during the Raccoon City outbreak, UBCS mercenaries were provided with drugs to prevent infection. However, at least one mercenary, Murphy Seeker, was infected with a drug-resistant strain and had to be euthanized. Sgt. Nikolai Zinoviev, a mercenary with ties to Umbrella's secret police, was given a more advanced version of the drugs to reduce the chances of infection.

Umbrella also utilized antibody therapy as a treatment method, where antibodies from one patient are transferred to another to provide resistance. High-risk workers, including those assigned to Incineration Disposal Plant P-12A, were provided with these antibodies in tablet form. However, during the July 1998 outbreak at the factory, a novel t-Virus strain resistant to the prescribed antibodies spread among the workers, rendering the treatment ineffective. As a result, the workers succumbed to Cannibal Disease.[14] An independently developed antibody therapy known as Daylight was created by Dr. Peter Jenkins in 1998.[15] A sample of this treatment was successfully taken out of the city and became a recommended treatment for individuals recently exposed to the virus.[16] Additionally, a team at the Umbrella R&D Center developed AT1521, although all samples were destroyed, one of its creators, Dr. Linda Baldwin, was safely evacuated.[17]

At least two vaccines were developed for the t-Virus, showing some effectiveness when administered to recently infected individuals. While Umbrella likely had its own vaccine supplies, the earliest known vaccine was independently created in Raccoon City by surviving medical personnel at Raccoon General Hospital. However, all vaccine samples and research data were destroyed due to the city's destruction and Umbrella's attempts to eliminate evidence. S.T.A.R.S. officer Jill Valentine received treatment with this vaccine.[18] A second vaccine, known as the t-Vaccine, was developed by the WP Corporation in 2005 in partnership with the Pentagon. It represented the United States' commitment to neutralizing the threat posed by the t-Virus. The vaccine had successful trials in India and the American city of Harvardville, but a terrorist bombing of the laboratory complex destroyed the research data and left only one sample remaining.[19]

Known Infectees[]



  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. Cite error: Invalid <ref> tag; no text was provided for refs named DI
  12. Wikipedia: Viral Replication at Wikipedia
  13. Resident Evil: Revelations (2012), file: "Botany Plants with Medicinal Properties - 3rd Edition"
  14. Resident Evil 3: Nemesis (1999), file: "Manager's Diary".
  15. Resident Evil Outbreak (2003), file: "Peter's Diary".
  16. Resident Evil: The Marhawa Desire, issue 1: "Academy of Tragedy".
  17. Resident Evil Outbreak File #2, "end of the road"
  18. Resident Evil 3: Nemesis
  19. Resident Evil: Degeneration.