Sergei Vladimir is the Russian colonel of the Umbrella Corporation's paramilitary service and the main antagonist in the video game Resident Evil: The Umbrella Chronicles.
Recruitment into Umbrella
Sergei originally served as a colonel in the Soviet Union and continued to be referred to by this rank for the next 10 years. During his time there, his right eye was blinded. After the fall of the Soviet Union, Sergei was offered a powerful place in Umbrella by Oswell E. Spencer. The two became close friends and the former colonel became extremely loyal to his new employer, carrying out any of his commands by any means neccesary. Sergei became involved in tyrant research and helped to found Umbrella's mercenary force, the Umbella Biohazard Countermeasure Serivce. During his time in the corporation, he developed a rivalry with Albert Wesker, who he was suspicious of and believed would eventually betray Umbrella and Spencer. Sergei constantly punished Wesker for not following orders to the letter, though Wesker never seemed daunted by him. Despite their rivalry, the two held a mutual respect for one another. After finding out his genetic makeup was the rare one capable of producing a Tyrant, Sergei agreed to allow Umbrella to clone him and his DNA became the genetic model of most of the tyrants beyond the T-001 and T-002 Tyrants designed by the team in the Arklay Mountains. Sergei requested that two of the T-103 tyrants be re-engineered into his personal bodyguards, who would come to be called "Ivan". The 10 T-103's produced from Sergei's clones shaped every Tyrant model afterwards, such as the Nemesis.
Fall of Umbrella
Sergei became very involved with the scientific workings of Umbrella and, while not as intelligent as other noted Umbrella scientists, lead the creation of T-A.L.O.S., his Tyrant masterpiece. Eventually Sergei came to see the tyrants as his brothers, who would help to bring about a new age under Umbrella. After the T-Virus outbreak in the Arklay Mountains, Sergei met up with his old rival, Wesker, who he ordered his Ivan to punish for failing to retake control of the Management Training Facility. However Wesker escaped when the explosions of the self-destructing facility distracted Sergei and the Ivan. Afterwards the two headed to the Spencer mansion so as to get the T-A.L.O.S. prototype and as they were leaving, they confronted by a pack of Cerberus that the Ivan easily dispatched. Later, during the Raccoon City Outbreak, Sergei was sent to retrieve the U.M.F.-013 computer core, that had all of Umbrella's computer data loaded onto it. It was transported out on a helicopter that also carried an unnamed Umbrella officer, who thought that Sergei was too reckless for stealing the computer core from the company, even though it was on Spencer's orders. After the Raccoon City Outbreak, Umbrella was a sinking ship and Spencer needed to keep himself out of the public's eye. He named Sergei chief executive officer of what remained of the company, confident he could keep it afloat. Sergei moved the company's data and assets to a facility in Caucasus that was disguised as an oil refinery. Unfortunately a bio hazard broke out that killed 98% of the staff at the same time that Wesker chose to infiltrate the base, so as to obtain the U.M.F.-013's data. As he was making his way through the facility, Sergei confronted him again and this time, released both of the Ivans to finish him off. At the same time, Chris Redfield and Jill Valentine led an attack on the base, determined to finish off Umbrella forever. Wesker, having defeated the Ivans, confronted Sergei who released T-A.L.O.S. to take care of Chris and Jill, then mutated into a Tyrant himself in a last ditch effort to kill Wesker. Despite his new abilities, Wesker still defeated and destroyed him, then took the data.
Sergei is a skilled marksman from his days in the army and known to be quite intelligent. After becoming a Tyrant, he gained superhuman abilities and a long tentacle from his fused together arms that could grab his enemies and help him move with incredible speed. However it is shown that his power came at a price as he seemed to enjoy the blows of pain Wesker administered to his weak point, indicating a loss of sanity from his transformation.