Tyrant was a series of experimental and mass-produced Bio Organic Weapons developed by the Umbrella Corporation to serve as potential supersoldiers.
In the 1960s, Lord Oswell E. Spencer, Dr. James Marcus and his student Brandon Bailey discovered the Progenitor virus in West Africa. The Progenitor virus possessed mutagenic characteristics, which would drastically alter the physical and mental makeup of its host.
Marcus and Spencer planned to use the virus to create biological weapons, forming the Umbrella Corporation along with their mutual friend, Sir Edward Ashford. Following Ashford's death in an experiment with the virus, Marcus soon began to work on the prototypes of a malicious biological weapon.
After years of experimentation, Marcus and Spencer realized that the Progenitor virus experienced trouble bonding with its host's DNA. Marcus managed to resolve the issue by infecting a parasitic organism that had a simple-minded purpose in life (to feed, specifically) with the virus and allowing the organism (in this case, a leech) to attach to another organism. This groundbreaking discovery led to more research, eventually leading up to the creation of the t-Virus, named by Marcus. Once an organism is infected with the new virus, it will eventually mutate into a deadly organism.
According to research conducted by the Umbrella Corporation, only one in ten million(0.0000001%) hosts exposed to the t-Virus possesses the potential to mutate into a Tyrant. This is a unique characteristic carried over from the Progenitor virus's own genetic compatibility to certain subjects. 10% of the total population will retain natural immunity to the t-Virus, even if directly exposed.
If the virus is able to find a suitable host, it will dramatically increase one's size, strength, speed and agility. It will also lead to the massive development or reconfiguration of bone structures causing large claw-like formations to rise from the host's body. While t-Virus is rather advantageous to its host, it should be noted that the subjected host will be forced to endure a prodigious increase in adrenaline, causing the heart to expand and protrude through the chest. Furthermore, most of the original breeds of Tyrants were plagued with grotesque facial deformities, as well as an acute decline in intelligence.
The first human to ever exemplify the characteristics of a Tyrant was Lisa Trevor. During her teenage years, Lisa was abducted by a group of Oswell Spencer's henchmen. Ever since the abduction Lisa has undergone a
plethora of experiments with the Progenitor virus and its many variants, which have led to her immense physical and mental deterioration. Albert Wesker, James Marcus' protegé, ordered that Lisa be slain in an undisclosed portion of the Arklay Mountains in order to avoid future "mishaps".
Many Tyrants have been seen to posess a heart on their right side. This is not an indication of Dextrocardia, but is actually the result of Umbrella's experimentation. In order to support the body to acceptable parameters, Umbrella researchers grafted one or more hearts to the body, either taken from larger animals such as rhinoceroses or cultured in the lab.
A "Super Tyrant" is the product of a Tyrant bypassing its Power Limiter, a device developed by Umbrella that prevents a Tyrant from experiencing out-of-control mutations. Usually, this only happens when a Tyrant suffers significant damage, and results in the tyrant in question gaining more muscle mass as well as claws. Super Tyrants are noticeably more difficult to dispatch than regular Tyrants. The Super Tyrants also lose all orders that they were given, turning into a berserker-like state.