"VECTOR" is the codename of an operator who served in the ranks of the Umbrella Security Service (U.S.S.), an elite paramilitary division of the Umbrella Corporation. Prior to the Raccoon City outbreak of September 1998, VECTOR was assigned as a recon to the newly constituted U.S.S. Delta Team, nicknamed "Wolfpack". Like the other members of Wolfpack, VECTOR's uniform was heavily customized, both in technology and appearance. The suit's unique features included a built-in active camouflage, enabling the wearer to become invisible for a short period of time, and technology that allowed him to mimic another person's appearance as well. Trained in martial arts by fellow U.S.S. agent HUNK and several Japanese masters, VECTOR's fighting prowess – particularly in knife combat – was held in high regard by his superiors.
When much of the population of Raccoon City became infected by the t-Virus, VECTOR and his teammates were ordered by U.S.S. Command to carry out Operation: Raccoon City. Their assignment held the highest priority as the company's very survival depended on Wolfpack's success. In addition to various side missions, Wolfpack was given two main objectives:
To destroy any and all evidence that could potentially damage Umbrella's public relations.
Little is known about the background of the operator known as "VECTOR;" his true name and origin remain a mystery. After becoming employed in the ranks of Umbrella Security Service (U.S.S.), an elite paramilitary unit and subsidiary branch of the Umbrella Corporation, VECTOR was sent to Rockfort Island where he honed his skills as a soldier. Having developed a highly lethal proficiency in martial artistry – especially in knife combat – under several Japanese masters, VECTOR's fighting prowess was ultimately noticed by HUNK, one of Umbrella's best operators who took a special interest in the new recruit's potential. After VECTOR fought HUNK in single hand-to-hand combat to a draw, the U.S.S. veteran personally oversaw the young trainee's progress.
Once his training was complete, VECTOR proved to be one of Umbrella's most effective assets; his achievements-in-the-field were matched only by his former mentor, HUNK. The Corporation noted how his movements were instinctive and smooth, in contrast to his motionless behavior when at rest. Given his skills in stealth and reconnaissance, Umbrella determined that VECTOR was ideal for the role of recon in the reformed U.S.S. Delta Team; the previous unit having been annihilated during an assignment on the Ecliptic Express. Although VECTOR and HUNK preferred to continue working together as they had a low tolerance for anyone of lesser skill, the company felt that their interests would be better served by distributing their two top assets into separate teams, rather than focusing them both in a single unit. Hence, VECTOR was assigned to fellow U.S.S. operators LUPO, BERTHA, FOUR EYES, SPECTRE, and BELTWAY in the new Delta Team, otherwise known as "Wolfpack."
In late 1998, Wolfpack was dispatched to assist the U.S.S. Alpha Team, led by HUNK, during its infiltration of a secret research facility located beneath the midwestern American urban area of Raccoon City. Although VECTOR initially had misgivings about his superiors' orders to kill the facility's U.B.C.S. guards, given that they also worked for Umbrella Corporation, he was nevertheless pleased to be serving alongside his former master once again. Their primary objective was to retrieve a sample of the experimental G-Virus from its creator, Doctor William Birkin, a rogue scientist who betrayed the company by plotting to sell the G-Virus to the United States government. Although both teams successfully obtained Virus, Birkin – infected by his own creation – ambushed the group, killing most of HUNK's Alpha Team. Evading the mutated scientist, HUNK ordered VECTOR and the rest of Wolfpack to evacuate the facility while he remained behind to complete the mission.
In the week that followed the incident in the underground laboratory, Raccoon City was devastated by the effects of Umbrella's t-Virus, which had managed to escape into the city's population, most of which died from the infection and became reanimated as "zombies." In order to ensure Umbrella's survival, U.S.S. Command determined that nothing could be allowed to link the company to the catastrophe that destroyed an entire city. Hence, VECTOR and his team were deployed for the commencement of Operation: Raccoon City, which entailed nothing less than the extermination of any kind of evidence, including survivors, that could potentially implicate Umbrellla Corporation in a number of "morally questionable activities," such as illegal experimentation and viral weaponry.