Hundred Demons.
That is not the name of a single entity, nor does it refer to precisely one hundred demons.
At least, in the world of jujutsu, its meaning is not so simple.
Just as Yase Doji is not the name of a single demon but a collective term for a group of them, the so-called Hundred Demons refers to a legendary gathering of yokai, demons, and spirits.
Some of them appear in mythology, some originate from folklore. Some are immensely powerful, while others are weak. However, without exception, they are all well-known.
For example, the Nekomata.
For example, the Kappa.
For example, the Yuki-Onna.
These well-known beings all belong to the ranks of Hundred Demons.
Hundred Demons can almost be said to encompass all the famous yokai and demons from Japanese legends, including even the Three Great Yokai—Shuten Doji, Tamamo-no-Mae, and the Great Tengu.
Throughout jujutsu history, there has been a recorded event where countless yokai and demons appeared together and paraded through the night.
Thus, the legend of the Night Parade of a Hundred Demons was born.
Phase 4 refers to a massive spiritual disaster at its core, triggering a chain reaction of countless other spiritual disasters. If severe, it could lead to numerous Phase 3 disasters manifesting and ravaging the city, hence being metaphorically called Night Parade of a Hundred Demons.
However, that is merely a metaphor.
The true Night Parade of a Hundred Demons has only ever occurred once in the history of jujutsu.
A parade where all kinds of yokai and demons appeared together—how could such a phenomenon happen frequently?
Moreover, over the course of a thousand years, many of the famous beings within Hundred Demons have long been hunted down and exterminated.
For instance, among the Three Great Yokai, Shuten Doji was slain a thousand years ago by Minamoto no Yorimitsu, and Tamamo-no-Mae was personally defeated by Abe no Seimei, the ancestor of the Tsuchimikado clan. Even the Great Tengu fought against the Tendai Sect in the Kamakura era and was ultimately defeated, never to be seen again. Some claim it was eradicated, leaving only its descendants and followers behind.
Given this, the true Night Parade of a Hundred Demons has long since become nothing more than legend. Many even believe it was nothing but fantasy, having never actually occurred in history.
Did the real Night Parade of a Hundred Demons ever truly happen?
No one knows.
But what people do know is that today, the true Night Parade of a Hundred Demons has appeared.
"BOOM—!"
It was the cry of the atmosphere itself.
As a magic circle, dark as the abyss with a tinge of violet, spread across the land of Tokyo, the very air within the city seemed to be infused with an alien presence, resounding with a deafening roar.
Countless buildings trembled.
The sky seemed to suddenly darken, as if the sun and moon had vanished.
And then—
From within the magic circle, a horde of yokai and demons began to emerge.
A massive blackened tree, radiating miasma, suddenly sprouted.
Ghostly hounds howled toward the heavens.
A hauntingly beautiful female specter emerged, wrapped in torrents of water.
Mirage-like flames flickered and burned.
Beyond that, resplendent firebirds took flight.
Weasel-like creatures, yet capable of breathing fire, leaped forth.
Zombies and mountain demons, one after another, crawled out of the magic circle, roaring, shrieking, and bellowing as they made their presence known to the world.
Tokyo had become a demonic realm.
"W-What...?"
Terror filled Amami Daizen's face.
"Impossible!"
Yamashiro Hayato shouted in disbelief.
"How could this be...!?"
Kogure Zenjirou gasped.
"...!"
Ohtomo Jin's expression darkened.
"This..."
Even Kagami Reiji was shaken, unable to believe his eyes.
As for the professional onmyoji, their teeth chattered as they trembled uncontrollably, their faces pale with horror, rendering Kurahashi Kyouko utterly speechless.
The creatures before them were not only unfathomable in number but included many beings that had previously existed only in legend.
Yet now, all of them had appeared.
Here, in Tokyo.
"Go."
Standing at the center of the abyss-like magic circle, Rozen, like the ruler of hell—the King of Hundred Demons—gave a cold command.
"Raise hell to your heart's content."
With those words, the yokai and demons let out ear-piercing laughter, their voices a mixture of deranged cackles and furious roars, before scattering in all directions.
"AAAAAAHHHHHHH—!"
Screams of terror erupted from the throats of all present.
And Tokyo plunged into chaos.
Later generations would speak of this day with fear.
"The skies of Tokyo were filled with yokai and demons."
"They rampaged through the streets, causing wanton destruction."
"They drifted through buildings, haunting every corner of the city."
"Structures crumbled in flames."
"Roads and vehicles were either demolished or occupied."
"It was a living hell."
Thus read the records of the future.
And reality was no different.
Countless yokai and demons soared through the skies of Tokyo, laughing and shrieking as they laid waste to the city, toppling buildings one after another.
On the streets, countless demonic creatures surged forward.
Some shattered vehicles.
Some tore down streetlights.
Some cracked the asphalt beneath their feet.
Some pursued the fleeing crowds, forcing people into a panicked stampede filled with screams, cries, and despair.
Smoke and fire began to rise across various districts, turning Tokyo into a battlefield—not one under bombardment by fighter jets and bombers, but one overrun by yokai and demons.
It was a disaster.
It was a nightmare.
And yet—
Later records would note something miraculous about this day.
"Astonishingly, there were no human casualties."
The yokai and demons rampaged, chased people, and terrified them, but none of them took a single human life. At most, they wounded or frightened them.
The onmyoji, though terrified, mustered their courage and engaged in battle against the horde of yokai.
Jutsuryoku, spiritual energy, miasma, demonic aura, and ghostly qi clashed, distorting and twisting the air in chaotic turbulence.
But there were simply too many yokai and demons.
The strongest among them were legendary figures.
The weakest, mere lowly spirits, were still vast in number.
No matter how many were slain, they could not be eradicated.
Despair began to take root in the hearts of the onmyoji.
And then—
A demon king wielding a sake gourd led an army of ogre(oni) to attack the Exorcism Bureau headquarters.
A peerlessly beautiful fox woman, adorned with nine tails, led a host of yokai to assail the Onmyo Agency.
A Great Tengu, commanding his brethren, continued to lay waste to one onmyoji facility after another, shattering the morale of all Onmyoji in their path.
This was the true Night Parade of a Hundred Demons—the greatest disaster since the Great Spiritual Calamity orchestrated by Tsuchimikado Yakou half a century ago.
People would come to call this day "The Day of Ten Thousand Demons."
Others would name it "Demon Fest."
Eventually, this day became an annual national festival, where people prayed to Hundred Demons for protection and performed rituals to ward off disaster.