War of Infinite Worlds

The War of Infinite Worlds (無む 限げん 大だい  世せ  界かい の 戦せん  争そ) was an omniversal apocalyptic conflict that resulted in the destruction of all universes, and the recreation of a single positive matter universe (and an antimatter universe, albeit briefly) at the dawn of time. It was the final war in the eternal conflict between good and evil, which eventually led to the extinction of literally nearly everything in existence.

The war is the primary highlight of the events of the Cross Crisis series, particularly in Project X Zone 3: War of Infinite Worlds, Super Project Cross Tag Battle: Destiny and Chou Super Robot Wars.

The Beginning
The roots of the final war are traced back at the very beginning of time when God created a single universe so that light and life can flourish in the vast infinite void. Heaven, the realm of angels, was also created. However, Lucifer, the most powerful angel in the realm, led a massive billion-year-long civil war in Heaven and attempted to overthrow God by traveling back to the dawn of creation and become the center of all existence. But the plan failed and as a result, the once-singular universe split into an infinitesimal multitude of parallel dimensions and alternate universes called the Omniverse. Eventually, after near total casualties on both sides, the civil war was won by the Army of Heaven led by Michael and the remaining angels of the rebellion, including Lucifer and his seven generals, were banished to Hell.

As a result of the multiversal split, a universe made entirely of antimatter was created and the primordial void of nothingness that existed before Creation was given a physical form and a new identity: the Anti-God, the progenitor of all evil, darkness and chaos.

From there, Lucifer would become Satan, the Great Dark God of the Nameless Void and the ruler of all evil. For billions of years, he and his hellish empire ruled over the Earth that would be called Earth-777, the "corpse of the once-single universe" and mankind that populated the world, in a seemingly never-ending age of sin, horror and deception, until the sacrifice of Jesus Christ, the Son of God, to free humanity from the clutches of sin. Enraged at his first defeat since his banishment, Satan forged the false religion Islam in attempt to destroy Christianity and drag the world down to chaos once again. While Satan started to once again exert his influence over Earth-777, his aura of evil would spread across quadrillions of universes in many eons to come.

Namco × Capcom
Countless ages later, being from the Antimatter Universe banded together and founded the organization notoriously known as Ouma, for the purpose of spreading chaos to many worlds wherever they may go. To counter this threat, Shinra was founded.

Trivia

 * The War of Infinite Worlds draws inspiration mainly from the biblical Apocalypse and the events of the 1985 DC event crossover Crisis on Infinite Earths. However, some allusions to Ragnarök of Norse mythology are made.