Vi is the virtual intelligence computer that was partly in charge of operating and running the Center for Disease Control building in Atlanta. It is heard in the last two episodes of Season 1 of AMC's The Walking Dead.
It is unknown when Vi was first activated; however, Vi was the main super computer that saw to the day-to-day operations at the CDC. It was the public address system used throughout the CDC, relaying audible messages and announcements throughout the building with a female voice, as well as gathering and storing data on diseases, experiments, and research that went on throughout the building. Vi was also commanded with specific instructions that in the event of a major power loss or terrorist attack, high-impulse thermobaric (HITs) fuel-air explosives are to be released which produces a blast wave of significantly greater power and duration than any other known explosive except nuclear. This is an extreme measure to protect the public and ensure that no infectious diseases escape the facility.
When the outbreak occurred, the scientists at the CDC began to give up on trying to find a cure, slowly leaving Vi in charge of the building. When Candace and Edwin Jenner were the remaining scientists left, Vi recorded the data of Candace when she was infected, being Test Subject 19 to allow Edwin to find a cure. While Edwin tried to find a cure, Vi was left in charge of the building and backing-up all data and saving power from all non-essential systems as well as communicating with Edwin Jenner.
Vi was documenting all of the video diary logs of Dr. Edwin Jenner and uploading it to anyone else who was listening. While Dr. Edwin Jenner was working in one of the Bio-safety Level 4 labs, he accidentally mixed toxic chemicals together on a sample which caused Vi to alert that the air quality has been compromised and that a full lab decontamination was required. Once Dr. Jenner exited the lab, Vi sterilized the lab with fire burning all samples along with it and preventing Edwin from continuing his development of finding a cure. While Edwin was giving up hope inside the CDC control room, Vi alerts Dr. Jenner that the sensors were detecting movement outside the building. Edwin checks the computer screens and discovers Rick Grimes' group outside. He eventually commands Vi to open the doors and allow Rick and his group to enter the CDC building.
Once everyone is inside the building, Edwin commanded Vi to re-seal the main entrance and shut down all power. Vi was formally introduced to Rick and the group of survivors. Once everyone was settled in, Dr. Jenner gets Vi to show him what he knows about the disease and gets Vi to show all his research on Test Subject 19. Everyone watches as Vi shows the 3-D MRI image of TS-19. It shows that the disease, transmitted via the bite, invades the subject's brain similarly to meningitis, after which it causes major organ failure and then total brain shutdown. Some time later, it restarts the brain stem which allows basic mobility and instinct. Jenner continues, telling everyone how the brain's Neocortex (responsible for higher order thinking and other 'human' traits) does not come back after death, and that a walker is simply an empty shell, driven by nothing but 'mindless instincts'. Despite the in depth scientific analysis given by Vi, Dr. Jenner adds that they are unaware of the disease's biological origins. Dale Horvath then inquires about a clock that was counting down to which the group finds out leads to a full facility decontamination. Dr. Jenner refuses to answer what happens when the counter reaches zero. The group asks Vi, who tells them about the HITs. Realizing that the facility is losing power, Vi announces at the thirty minute mark that the facility is prepping itself for the full scale decontamination event. It begins to shut down all non-essential systems and power to try and keep itself running for as long as possible. Not being able to conserve anymore power, Vi deployed the HITs following protocol and destroyed the entire Center for Disease Control and itself killing Edwin and Jacqui inside.
This list shows the victims Vi has killed:
- Itself (Suicide)
- Edwin Jenner (Caused)
- Jacqui (Caused)
- Greg (Caused)
- Numerous amounts of zombies located outside of the CDC when it exploded.
- Vi was voiced by Judi Durand, who also provided the voice of the Computer System on Star Trek: Deep Space Nine.
- Although Vi is clearly a fast and powerful computer with the ability to decipher voice commands and complete them, it is unable to make specific decisions on its own. It was programmed to follow the protocols set forth by people and would only respond to any inquires made by the CDC staff (such as Dr. Jenner).
- The name "Vi" may be a reference to Vi – one of the most popular Unix text editors, written in 1976.
- In the original teleplay script for "Wildfire," Vi was given the name of Vox and appeared to demonstrate a degree of sentience when communicating with Dr. Jenner.