Alright, now for the basic history:
In 1988, a man named Roy Curian approaches Umbrella CEO Oswall Spencer wishing for some support in his projects along with his other supporter the DBR corperation. Interested, Spencer approves and gives Curian his lab equipment for his research on life and death in his mansion somewhere in Europe. However, in three years, Curian's research comes to it's first test in Bayou City, Louisiana. That was when the US government sends rookie agent G to investigate the dissapearances in the city. G's report states that the citizens were made into some sort of non-living creatures under the control of the local prison warden Clement Darling. This is when the US government became interested in this event and began investigating Bayou City more thoroughly. This investigation lasted only five years. This was when the Arkalay Mountain killings were being investigated by Raccoon City's STARS (Special Tactics and Rescue Squad) team. Sadly, however, when the team returned with only Chris Redfield, Jill Valentine, Barry Burton, Rabecca Chambers, and Brad Vickers, they reported that Albert Wesker, captain of STARS alpha team, betrayed STARS and was one of the people involved in the Arkalay Mansion incident. Meanwhile, Agent G, now better experienced, was sent to save scientists under Roy Curian. Along with Thomas Rogan, they clear out the mansion of these "zombies" and saved the scientists. Bothof these incidents occured months before the dreaded Raccoon City incident, where the t-virus was released and rapidly multiplied in the victims. In the end, the US government decides to destroy the city with a nuclear missle.
This was called the Age of Zombies because of the increase of zombie incidents that occured. In 2000, the Curian Mansion was investigated again. In 2003, the US'es anti zombie group AMS was attacked by the Curian Mansion zombies. That next year, Leon Kennedy, survivor of the Raccoon City incident, was sent to rescue the president's daughter Ashley Graham from a newer threat, the Las Plagas and the cult Los Illuminados, lead by Osmund
Saddler. In 2006, the Willemett Parkview Mall in Colorado was also attacked by zombies. Three years later, the Green Flu mysteriously appears and turns the USA into chaos while BSAA (Bioterrorism Security Assessment Alliance) sends Chris Redfield and Sheva Alamor to investigate this incident. Two years after that, Fortune City, Nevada, was attacked by zombies as well as the the island Banoi, off the shores of Papua New Guinea. However, eight years later, the entire world is engulfed in a zombie infestation.