January 22, 2027: Dr. Hagiru Sato and his team of scientists from Japan, America, Canada, and Britain begin work on a matter-energy transference machine.
February 11, 2033: First machine is tested successfully after over a hundred failed tests. Controversy over the destructive nature of the technology ignites.
July 18, 2033: A catastrophic incident with an energy-matter machine destroys the city of Hiroshima, in devastation not seen since the atomic bombs were dropped nearly 90 years prior. Japanese government officials move to ban work on this technology, though Western powers urge them to allow it, despite the mishap.
April 22, 2035: First sighting of infected individuals. Most are animals, some humans are also shown to be susceptible to infection. Most seen around the ruins of Hiroshima, which had not been rebuilt.
May 13, 2035: Northern Japan is split off from its southern half as a nation-wide quarantine is enacted. Anarchy soon spreads through the infected regions. 15% of humans exposed to the disease are immune and show no side effects. 84.9% are affected fatally by the disease, which causes cancerous growths. 0.1% of those exposed are shown to successfully mutate. The "virus" is found to be a spreadable corruption of genetic material, which causes rapid mutations in infected individuals. All large animal life is soon infected.
January 1, 2040: 98% of all animals in Japan are wiped out; ecosystems ruled entirely by infected individuals.
May 8, 2048: Japanese Defense Force engages infected individuals to preserve quarantine. Co-ordinated attacks by infected humans and animals are seen. High levels of intelligence confirmed.
May 10: They fail, and the nation of Japan ceases to exist.
October 13: The United States Carrier George W. Bush is attacked and sunk by an unknown force. Later revealed to be a co-ordinated assault by the infected. Use of atomic weapons to destroy all life on Japan considered, but denied.
February 12, 2052: Remaining inhabitants of Japan have appeared, by outward observers, to have begun adopting the infected into their religions. Part of this religion is a total-weapons ban, and the banning of violence against infected individuals. This is surprisingly effective at ceasing conflict with infected individuals.
April 2, 2055: Infected seen to have spread to North America. Military preparedness results in a far more contained infection. Hundreds of thousands in the United States, Canada, and Mexico die.
March 11, 2061: The United States Army begins experimenting with the combat prowess of infected animals, who are shown to have a friendly connection to humans who treat them well, much like dogs. Initial tests exceed expectations. Later that same year, China, Russia, Vietnam, and N. Korea react by signing the Kommu Pact, ensuring protection against the now utterly overpowered West.
July 2, 2063: The Kommu alliance declares war on the United States. Infected used to great effect.
November 9, 2066: The war ends. Communist states are dissolved, China and Russia (and all of Asia) are now under the jurisdiction of the NATO.
December 25, 2072: The now divided regions that were once Japan begin to open up to the outside world. Mostly through scientific trade-off.
February 1, 2081: Japanese scientists sneak into heavily infected Brazil. They recover the DNA of one of the individuals believed to be one of the first infected.
Beliefs are that the infected are actually the next phase in evolution, and to find one of the originals would better help their understanding. There are many tried and failed cloning attempts, before a final experiment is successful. The result of this experiment, capable of self-induced energy-matter transference, is responsible for the death of dozens before escaping.
May 22, 2081: Ash Ketchum turns 10 years old, and sets out on a quest to capture some of the strongest mutant animals known to man.