The Fall occurred three years after Yusuke Urameshi's tournament of kings chose Demon World's new ruler, three years after the revolution meant to reshape the demon planes forever, three years all marked by border patrols and human protection laws and peace.

Then came the Fall—the dissolution of the barrier between worlds.

There was no grand fight preceding its destruction, no war to protect the human world, no spirit detectives putting their lives on the line. One day, the barrier stood, and the next, it did not.

Demon World's great leaders never foresaw the Fall's arrival. Not King Enki, concluding his reign as ruler of the demon plane. Not Lord Mukuro or her right hand Lord Hiei Jaganshi. Not Yomi or his general Youko Kurama. Not Yusuke Urameshi on one of his infrequent trips to his lands in Tourin.

But the common folk knew.

The whispers had started four months before the Fall. They were quiet, little more than murmurings in dank taverns, soft as the wind blowing through the Forest of Fools. But when the time came, demonkind was ready.

Thousands of apparitions and fiends alike gathered on the massive plateaus sprouting from the world's sprawling plains. They stared into the sky. Demon after demon waiting for the ending of the world as they'd known it.

When the wall fell, the worlds shook, trembling and colliding as they touched in a way they had not for centuries. A vortex erupted in the sky, seizing the waiting masses and drawing them into the beyond.

Not every soul made it. The great divide between worlds tore the weakest spirits apart, shredding them like so much nothing beneath the crush of its power. But many survived, and when they landed in the soft soil of Human World, boots and claws and padded feet thudding down across the globe, nothing would ever be the same.

Author's Note: Just a prologue here. A setting of the stage. There will be more to come soon!