That day looked like any other in the Wild World. Daylight was just as bright as always, and the primordial Yin and Yang moved apart, each in its own isolated region.
But just minutes before the day ended, everything changed.
The primordial Yin and Yang started twisting violently. The two forces, which had always stayed separated, pushed forward and invaded each other's territory at the far north and south of that world.
To the south, in a vast region, the environment looked like an estuary, as if the waters of the ocean and river had met in a silent standoff. But in the north...
Over an area of more than ten kilometers, everything was swallowed by chaos. The two powers repelled each other, creating a raging gray zone.
