I Am the Variable

History takes a turn in despair. A hundred years ago, when the sky was like a broken mirror and countless cracks called "Chaos Doors" opened silently around the world, known civilization came to an end within a few weeks. The steel jungle was reduced to ruins under the claws of the more ferocious monsters, and the roar of guns was drowned out by the roar of despair. During that period, later generations would call it the "Great Collapse" - the era when humans were the masters of the planet came to an end. However, in the deepest darkness, a fire quietly ignites.