For almost 30 years, the Arklay Laboratory would serve as Umbrella's primary genetic and viral research facility. It was here that researchers William Birkin and Albert Wesker would conduct highly sensitive research into the Progenitor virus and its off-shoot, the Tyrant virus. This was also the place where Umbrella developed its first successful B.O.W.'s, including the prototypes for their popular Hunter and Tyrant series. In the late 1980's, Birkin would leave the Arklay lab and conduct his G-virus research at the Raccoon City Underground Laboratory. Wesker would also leave in 1991, taking up a career with the Raccoon police force as a secret Umbrella investigator.
In 1998, the Arklay Laboratory fell victim to the machinations of Dr. James Marcus, apparently ressurrected following his assassination ten years previously. Marcus had contaminated the facility's water supply with the T-virus, allowing it to spread rapidly among the staff, turning them all into zombies. As the lab staff succumbed to the virus, security procedures failed and various bio-weapon specimens were released into the surrounding wilderness. Weeks following the initial contamination, a number of brutal murders took place in Raccoon City. Due to the nature of the killings, the police department suspected the murders to have been perpetrated by some kind of cannibalistic cult. The Special Tactics and Rescue Service (S.T.A.R.S.) was mobilised to investigate the murders, but shortly after Bravo Team was sent into Raccoon Forest, contact was lost. The Alpha Team was sent in 24 hours later to continue the investigation and find Bravo Team, which led to them finding the Spencer Mansion and the horrific monstrosities that lurked within.
The entire investigation had been sabotaged from the beginning by Albert Wesker, the S.T.A.R.S. captain, who was under orders from Umbrella to gather combat data on the bio-weapons running loose in the Arklay facility by pitting the S.T.A.R.S. members against them. Once all necessary materials and documents had been secured, Wesker was to activate the lab's self-destruct mechanism and destroy it completely, removing all evidence of Umbrella's illegal activities.
As the S.T.A.R.S. continued their mission, they discovered the laboratory hidden beneath the mansion and uncovered Wesker's involvement with Umbrella. After fighting their way through Wesker and the monsters within the lab, the S.T.A.R.S. made their escape before the facility self-destructed, destroying all the remaining creatures and the source of the T-virus... Or so they believed.
Below is a list of creatures that populated the Arklay Laboratory.
- MA-39 Cerberus - Doberman hounds injected with the T-virus deliberately to determine their potential as B.O.W.'s. While created in the laboratory, the dogs had escaped up to the Spencer Mansion above and into the surrounding forest by the time of the S.T.A.R.S. investigation.
- MA-121 Hunter "α" - The first Hunter model was originally produced in the Arklay lab. During the Mansion Incident, most of the Hunters remained caged until Albert Wesker released them during the S.T.A.R.S. investigation. The majority of the Hunters had by then moved aboveground into the mansion, though some dwelled within the catacombs.
- Chimera - These monsters remained confined to the laboratory area, hiding in the ventilation ducts and emerging to surprise the S.T.A.R.S. members as they explored the facility.
- Lisa Trevor - Umbrella's longest-surviving test subject. She had been forced to endure dozens of experiments with multiple viral strains which turned her into a near-indestructible monster. She escaped the lab level during the outbreak and roamed through the mansion's courtyard and catacombs.
- Zombies - The Umbrella staff who worked in the mansion and lab were all infected with the T-virus and turned into undead husks that hungered for living flesh.
- FI-3 Neptune - Located in the lab's Aqua Ring, these sharks were used as guinea pigs to test the T-virus' effects on aquatic life. The results were disappointing; the sharks only underwent minor mutations. All specimens were killed when the S.T.A.R.S. drained the water out of the Aqua Ring.
- Plant 42 - The roots of Plant 42 reached down into the Aqua Ring while the main body was located in the Arklay Dormitory. Chris Redfield and Rebecca Chambers were apparently able to introduce a V-Jolt chemical into the root that was able to kill off the plant.
- Tyrant T-002 - One of the original Tyrant models. This model had been rendered obsolete with the development of the T-103 in Europe and remained in suspended animation until it was activated by Wesker. The creature fought against the S.T.A.R.S. but was killed on the mansion's helipad when Chris blew it up with a rocket launcher.