This virus increases the metabolism of its host, giving them incredible superhuman strength, speed, agility, endurance, and healing factor. The only known host of the virus is Albert Wesker, so most knowledge of its effects comes from observations of him. Its healing factor and superhuman endurance at least also kick in as soon as the subject is infected.[notes 1]
The virus' effects limits itself to muscle tissue and the lower organs, leaving the brain relatively intact. This breakthrough means that the subject's mind is retained and no ill effects take place provided they carry a special gene for adapting to the virus.
The virus has a unique effect on ocular tissue. The only visible effect of the virus is the way in which it affects the subject's eyes. Wesker demonstrates the ability to move faster than the human eye can see, at least in short bursts, which indicates he is capable of processing visual information much more quickly than a normal human. The eyes appearance likewise is altered have its pupils narrow down to resemble slits, similar to a cat or a reptile, and the eyecolor is also altered to be yellowish-red. In addition, the eyes also developed a form of periodic bioillumination, glowing a deep shade of red whenever he feels an intense emotion, such as anger. Despite this, however, the virus does not have much impact on light-based visual processing of the eyes, as proven when Chris Redfield turned out the lights and it blinded Wesker due to his sunglasses being used in the dark, which ultimately led to his poisoning.
The virus is very unstable, so the host has to use a special serum to keep it under control. The serum itself must be given in very precise dosages, lest it act like more of a poison and damage the host from the inside.
Apparently, the virus can only supply enhancements to those who survived the virus to those who had a perfectly healthy body, as Alex Wesker, the only other known surviving recipient of the virus, only simply survived the infection due to a preceding illness that she had been suffering from.
The strain was developed for use in "Project W", advanced by Oswell E. Spencer as part of a special screening process for identifying the most genetically-gifted of the Wesker children. Only two of the thirteen remaining test subjects survived: Albert and Alex Wesker, having survived largely due to special genetic markers, which allowed at least Albert to enjoy all the benefits various viruses had, and absolutely none of their drawbacks apart from needing to inject a serum regularly to keep the virus stable.
- In the Japanese version of the Virus Memo in Resident Evil: Umbrella Chronicles, it is made clear that the virus doesn't actually revive the dead host, but rather strengthens the host enough to only render them unconscious from otherwise extremely fatal wounds, as well as heal them within five minutes to wake up.