Little is known about Vector’s background except that his nationality was confirmed to be Japanese and his real name or age has never been officially documented. He possessed extremely impressive close-quarters-combat and hand to hand skills, leading many to believe his early past was spent training with Japanese masters as his martial artistry was extremely impressive. His movements were always instinctive and smooth; this was a complete contrast to when he was at rest, often standing as motionless as a statue.
It is unknown when Vector was first employed by Umbrella but it has been confirmed he spent time at a combat training camp on Rockfort Island under the watchful eye of U.S.S. Alpha Team leader, Hunk.
Vector held an ice-cold disregard for anyone he believed to be his inferior but he saw that Hunk had even more impressive skills than his own, leading him to look up to Hunk as a role model. During his time on Rockfort, Vector honed his skills against the likes of former Russian Spetznaz operatives and had an affinity for using knives for stealth. Guns in his opinion were too loud. He also tested his skills against Hunk in mock combat, leading his mentor to acknowledge his skills and brand Vector as the most impressive trainee of all the recruits. The two men developed a mutual respect for each other’s abilities.
Hunk noted in his evaluation report that he would like to further develop Vector’s training by having him temporarily join Alpha Team on live operations. But instead Vector was eventually assigned to the new U.S.S. Delta Team, code-named Wolfpack where Hunk’s influence would live on. He had indicated he would like to continue serving with Hunk but was informed that the corporation would be better served at that time if they operated on separate teams. Nevertheless, Vector retained hope that an opportunity would come where they could work together again. As it transpired, that opportunity came sooner than expected as in September 1998, Wolfpack were ordered to assist Alpha Team during their infiltration of the underground lab in Raccoon City to steal a G-Virus sample from William Birkin. Proud to be fighting alongside Hunk once more, Vector and his team engaged U.B.C.S. guards and later Spec Ops teams that arrived to defend Birkin. But the mission went wrong when Birkin was fatally wounded and injected himself with his own creation. He mutated into a horrific monster and came after them. In the end, Hunk ordered Vector and the others to leave him behind.
Wolfpack were sent back into the city days later to destroy evidence linking Umbrella to the outbreak. Vector kept the team alive on several occasions and developed an instant dislike for Nikolai when they encountered him in City Hall. Vector and Wolfpack completed successful objectives at City Hall, Raccoon General Hospital and the R.P.D. before they were ultimately abandoned by Umbrella. It remains undetermined if he ever escaped Raccoon City alive.