Abe no Seimei—the most brilliant onmyōji in Japanese history—flourished during the mid-Heian period. His father was a human, Abe no Yasuna, and his mother was the yōkai Hagoromo Gitsune, making Seimei a half-human, half-yōkai hybrid.
A thousand years ago, humans and yōkai ruled in shifts—humans by day, yōkai by night. In the daylight, Abe no Seimei was a revered onmyōji who could manipulate the tides of the nation. In the dark, he was the sovereign of shadows, ruler of demons, commander of all monsters.
Thus, Seimei believed: So long as I live, the world's order will not collapse. So long as I endure, this world will one day become paradise.
Obsessed with that conviction, he poured his efforts into researching immortality.
Then, one day—a high-ranking official, taken in by the myth "consuming a white fox's liver grants eternal life," sent men to kill Hagoromo Gitsune. Not only did he have her slaughtered, he even brought her corpse to Seimei's face and demanded he turn it into an elixir of immortality.
Betrayed and disillusioned, Seimei snapped. He exterminated the official and every one of his retainers.
"Humans are fools. They destroy the balance between man and yōkai for selfish gain. The moment they're left unchecked, they grow arrogant. At this rate, this beautiful world will collapse from their idiocy."
With that, Seimei renounced his role as peacekeeper and resolved to place yōkai atop the hierarchy. He would create a paradise for monsters—a world of eternal night.
Eventually, Seimei mastered the ultimate reincarnation spell: the Perfect Soul Rebirth. He would be reborn through his mother's womb, creating a closed loop of life and power.
This is how Hagoromo Gitsune became entangled with the Nura Clan.
To produce this perfect rebirth, she sought the finest quality fresh liver. She kidnapped Yōhime, the woman Nurarihyon loved, and was ultimately slain by him.
Later, Sanmoto's Left Eye manipulated Yamabuki Otome, the wife of Rikuo's father Rihan, into killing her husband. Yamabuki, devastated and overcome with grief, became the vessel for Hagoromo Gitsune's reincarnation.
Not long ago, Hagoromo Gitsune finally succeeded in birthing Seimei again in Kyoto.
Now going by the name Nue, Abe no Seimei repaid his mother by casting her into hell—and ascended as the ultimate final boss.
Because his new body was still flawed, Seimei spared Rikuo and the others for the time being. Perhaps he thought destroying them prematurely would not be worth damaging his perfection.
He returned to hell to purify himself and accelerate his body's evolution.
"It's close... So close..."
"Soon, I'll return this world to its proper order."
So long as he could walk the earth again, Seimei was certain: his perfect world would come to be, and chaos would cease under his control.
But on this day...
Something was off.
From the darkness of hell's purification spring, Seimei rose—naked, golden hair cascading behind him like molten light. His radiance stood in stark contrast to the infernal black waters of sin and karmic fire.
He paused his cleansing ritual and stepped out.
He sensed... noise. Something troubling beyond the walls.
His subordinates should be guarding the outside. He decided to check what was going on.
Back when Seimei cast Hagoromo Gitsune into hell, the Kyoto yōkai were divided.
Some, still loyal, stayed behind to protect her corpse.
Others, awed by Seimei's might, followed him into hell.
In addition, Seimei had spent a thousand years gathering native demons of the underworld—hellborn oni.
"Blackblade Mountain... really vanished?"
Among a group of hell yōkai, Ibaraki-dōji furrowed his brow. One half of his face was hidden, but the visible side showed genuine shock.
Blackblade Mountain was a range of obsidian peaks, each sharp as a blade. Even among hell's monstrous denizens, it was a place to be feared.
Though not native to hell, Ibaraki had once visited. He'd even tried hacking at the obsidian cliffs himself—then quickly given up.
So when someone told him the entire mountain had vanished, he thought it was nonsense.
Then he came. Saw it with his own eyes.
Gone. Completely gone.
The mountain that had stood since before any of them had consciousness—obliterated.
"And right when Seimei's about to return to the surface... Something stinks. This really pisses me off..."
Ibaraki looked behind at the gathered demons, then ahead to the crimson plain.
"This whole place reeks like fried blood and regret... Ugh. Whatever. I'll check it out. Not like I know why I keep doing this crap."
Grumbling, Ibaraki still stepped forward.
But the instant he moved, a pressure like a volcanic eruption blasted toward him.
He leapt aside just in time.
And then—a red meteor fell from the sky.
It crashed into the earth, triggering a massive wave of fire. Those hell yōkai who couldn't react were incinerated without even a scream.
Even Ibaraki, who had dodged, was staggered by the wave of heat.
The power of the flame startled him.
Being forced to evade—it enraged him.
The loss of the others? He couldn't have cared less.
"Who the hell dares attack me?!"
His voice echoed, sharp and furious.
"Hah? What the hell are you talking about?"
From the inferno, a small figure emerged.
The voice was young, but laced with wild arrogance.
"Who needs a reason to fight? Kill, devour, conquer—that's what it means to be an oni! Your stupidity shocked even me... If I had to give a reason, it's because I think you're annoying!"
A massive bone-like greatsword, wreathed in flame, was plunged into the ground beside her. The small figure seized it, hoisted it effortlessly, and sliced the firestorm apart.
She wore a yellow kimono, completely casual. Her long, fiery gold hair radiated heat. Her skin bore red demonic markings, and two sharp horns jutted skyward from her forehead. Her crimson hands and clawed feet were definitely not human.
Seeing the girl, Ibaraki was stunned.
There was still such a powerful, unclaimed oni in hell?
"The disappearance of Blackblade Mountain... was that you?"
"Blackblade what now? No clue. You dragged a bunch of demons in here and started yapping like some bureaucrat... Are you even oni?"
"You're dead!"
Ibaraki had never been known for patience. Enraged, he drew his blade and swung.
Clang!
His lightning-fast slash was caught mid-air by her bone sword.
"Yes! That's more like it!"
Her lips curled into a manic grin. Her fiery hair flared even hotter.
"If you're oni—fight me! I can't stand boredom or silence!"
She stomped, and the ground shattered. Webs of cracks spread from her feet. A flood of demonic force surged through her blade and into Ibaraki's.
"What the hell is this strength?!"
"Hey! Eyes up here!"
Before he could react, she dashed in like a blazing comet. Each step dented the earth.
By the time he came to his senses, she was already midair—blade raised for a crushing overhead slash.
"Here it comes! Meteor Annihilation! Wahaha!"
Her laugh was gleeful—like a child's game.
But the impact was anything but childish.
A crimson meteor fell. The flames flared higher. The land cracked, exploded. The shockwave lifted stone, shattered it, and melted it in heat.
Ibaraki dove out, his clothes scorched and torn.
Then—something moved.
From the fire emerged a spear of flame. A small form with sharp claws and a manic grin surged toward him through the blaze.
"Are you just gonna run?! Come on—fight me! Rip off my arms! Tear out my liver!"
This chick is insane!
Clutching his chest, Ibaraki scrambled upright—only to see her pull his sword from her own shoulder and casually snap it in half.
"Come on, I know you're not done! My blood just started to boil! Let's shred each other to bits!"
She's a damn lunatic!
Wiping blood from his lip, Ibaraki stared down the walking inferno.
"Ah! Almost forgot!"
She paused, then tilted her head.
"According to human... etiquette? You're supposed to give your name before a fight, right? Not that I care. Oni don't need rules. But Shuten keeps nagging me about it... So annoying."
She sighed, then slung her bone sword over her shoulder.
"Name's Ibaraki-dōji! Head of the oni of Mt. Ōe! The blazing terror of Rashōmon!"
Ibaraki-dōji: "???"
Did… Did I just hear my own name?
Ibaraki-dōji was dumbfounded.
"Hey!"
Still across the battlefield, the girl barked at him.
"I gave you my name. What's your excuse? Too scared to answer?"
There was a long silence.
Then, grimly, awkwardly:
"...My name is also Ibaraki-dōji."
"???"
The girl blinked. Then studied him. Up and down.
After a while, she asked, thoughtful:
"Why is Ibaraki-dōji a man?"
The blood nearly spurted from his mouth.
I was just about to ask why YOU'RE a girl! And you have the audacity to ask me this?!
"Ibaraki-dōji's obviously supposed to be a guy!"
He roared.
The girl frowned.
"What nonsense are you spouting? Of course I'm a girl! Otherwise how did I seduce that idiot Watanabe no Tsuna? Don't tell me you think he's into guys?"
In the legends, Watanabe no Tsuna—one of Minamoto no Yorimitsu's Four Heavenly Kings—encountered Ibaraki-dōji at the Suzaku Gate disguised as a lost woman. He took her home, only for her to reveal her true form. He cut off her arm with his sword, which would later become the famed blade Onikiri (Demon-Slayer).
"…"
Suddenly… his argument didn't seem so solid.
Sure, the Ibaraki-dōji in that tale had transformed into a woman…
But he had never learned any transformation arts.
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T/N: HUH??? HE MANAGED TO SWITCH HEROIC SPIRITS???????