To advance and evolve the existing system of power, it was essential to break the current balance — and that included Muzan, the progenitor of all demons.
Unless Muzan himself could evolve and introduce a higher‑order form of primal energy into this world, his existence had become nothing more than a limitation.
Merely turning humans into demons and relying on the power of blood alone was no longer enough.
This was exactly why Oboro had avoided meeting Muzan for such a long time.
In the early stages, he had only needed to make use of Muzan's influence to create chaos and raise the difficulty of survival.
This forced both the Demon Slayer Corps and his own inheritors to grow stronger through necessity.
A form of "constructive competition" had been established.
The moment Muzan was defeated would mean that either the Demon Slayer Corps or the inheritors had already evolved to a completely new level.
At that point, one of the inheritors would step into Muzan's place and continue the struggle against the Corps.
Yet the core purpose of the inheritors' will had always been to reshape the world — to destroy the old and bring forth the new.
This fundamental mission placed them in direct and permanent conflict with the Demon Slayer Corps.
Because of this, true peace in this world was impossible.
The fighting would go on forever.
As Oboro had once said: as long as there was conflict and struggle, there would always be the strongest possible stimulus for the evolution of power.
Given the current rate at which the Demon Slayer Corps was growing, Muzan would likely be forced out of the picture long before Tanjiro and his friends were even born — more than a hundred years earlier than in the original timeline.
Unless, of course, Muzan managed to devise something truly extraordinary.
After Oboro turned Gyutaro and his sister into demons, he infused them with a portion of his own essence blood, making them official members of the inheritors.
That very night, amidst the falling snow, Gyutaro began his revenge against the world that had wronged him.
His first act… was slaughter.
He slaughtered every person who had looked on in silence and done nothing to help.
Everyone living along the banks of the Rashōmon River was marked for death.
Oboro and Chiyo left before it began; he had no interest in watching the massacre unfold.
However, he intended to be fully involved in guiding Gyutaro's growth. From what he knew of the future, it was Gyutaro who possessed true strength, not Daki.
Her existence was significant only because of the "bond between siblings"… or to put it more bluntly — exactly as Muzan had once judged — she was nothing but a burden.
Yet it was precisely that bond which drove Gyutaro to become so powerful.
Love between family, lovers, friends — emotional bonds of all kinds were the very nourishment that sustained and strengthened inherited will… which meant there was no question of separating them.
The best Oboro could do was ensure Daki did not remain quite so weak.
He planned to teach Gyutaro martial arts, combat techniques, and the fundamental principles of energy cultivation and breathing.
His version of breathing was far superior to the low‑level styles used by the Corps, and it was applicable to any living being.
In other words — demons could learn it too.
Early the next morning, news of the massacre spread across the city, shocking everyone.
The scene resembled a living hell; every witness was left trembling in horror.
It was easily the most brutal and devastating demon attack in recent times, during what had otherwise been a period of relative peace.
Everyone now knew a demon was hiding within the city.
By this era, people were well‑informed about demons. Authorities and civilian demon‑hunting groups immediately began searching, yet found nothing — not a single clue.
In the end, they concluded the creature must have fled the area.
Oboro managed to suppress the details of the incident for a short while.
But in the current climate, it was impossible to keep such news contained.
Both the Shogunate, the Demon Slayer Corps, and the general population were highly sensitive to anything related to demons.
Rumors traveled fast, and within two days, members of the Demon Slayer Corps arrived.
They were able to respond so quickly because by now, the Corps was deeply integrated with the Shogunate.
Through the government's channels and authority, their "war machine" operated much faster and more efficiently.
Three Hashira had come in person.
With such a massive loss of life, it was clear the perpetrator was no ordinary demon, and they took the matter very seriously.
Oboro had already sent word to the Shogunate asking them not to interfere — yet the Hashira had come anyway. He was not surprised.
In the face of absolute conviction and duty, the Demon Slayer Corps would fulfill their mission no matter what, even if it meant defying authority.
However, after extensive investigation, the three Hashira found no trace of the hidden demon.
Eventually, their leads narrowed down to Oboro's residence.
But due to Oboro's high status and the heavy security surrounding his estate, they could do nothing.
They settled temporarily within the city, waiting for Oboro or someone inside to reveal a flaw or slip up.
---
"If you want to protect your sister, you must become far stronger… Starting today, you will train under me."
"If you fail to reach that level, what happened to Daki will happen again sooner or later… and next time, no one will come to save you."
"The only ones capable of saving you… are yourselves."
"The Hashira of the Demon Slayer Corps are already here. With your current strength, any one of them could kill you effortlessly."
Under the night sky, Oboro spoke softly, looking down at Gyutaro, who knelt before him wearing the black haori Oboro had given him.
Since becoming a demon, Gyutaro's appearance had changed, now matching exactly how he would look in the future.
The only difference was that he now wore clothing over his bare upper body.
Oboro was no longer speaking casually or lightly. Through his influence and guidance, the Hashira of this era were far more powerful than they had been in the original timeline.
Gyutaro possessed immense potential, but he had only recently become a demon.
Furthermore, unlike other demons serving Muzan, every inheritor retained their human memories — a gift made possible by the will contained within Oboro's blood, which preserved their clarity and sense of self.
"I understand," Gyutaro replied obediently.
Daki, standing beside him, was also subdued.
Her body trembled slightly.
Given Daki's arrogant and domineering nature, it was nearly impossible for anyone to make her submit.
When they had first met Oboro, Gyutaro had been forced to physically push her head down to make her bow in respect.
Even though she knew Oboro was the one who had saved both their lives, Daki could not help but glare at him coldly.
In her eyes, this man did not deserve such deference from her and her brother.
But the moment her eyes met Oboro's gaze, her expression changed instantly.
A deep, primal fear surged up from within her, overwhelming her arrogance and forcing her to hold back.
From that moment on, every time she saw Oboro, she dared not even look him in the eye.
In truth, Oboro had merely exerted a tiny fraction of his soul's power.
Otherwise, training and disciplining this girl would have proven nearly impossible.
"Let us begin," Oboro said to Gyutaro, glancing coldly at Daki but choosing to ignore her attitude.
"Yes, master."
---
"Can you feel it?"
"Yes."
"It is definitely there… I sense a demon's presence, and more than one."
"Should we breach the perimeter? It seems a person of high standing lives there."
At that moment, three figures stood atop a building not far from Oboro's residence, looking toward the compound hidden in the darkness and speaking quietly among themselves.
"But… before we came, the Master specifically instructed us: if we encountered a situation exactly like this, we were not to force our way in. We were to simply leave immediately." One of them recalled the order.
"It sounds as though the Master knows exactly who lives there."
"What does that mean? Just because he has influence and status, he can harbor demons? For all we know… he might already be controlled by them…"
Just then, a calm‑looking man with short hair spoke up. "Forget it. Let's go."
"What?"
The other two Hashira were confused by his decision.
"Yūta…"
The man called Yūta — the current Water Hashira — took a deep breath and explained. "My teacher once told me about events that happened here many years ago, during the time of a previous Water Hashira. He passed a warning down to every successor he trained: whenever something unusual related to demons occurred in this region — no matter how serious or how minor — we were to proceed with extreme caution. He specifically pointed to this location in the city… right there."
Yūta frowned as he looked toward the distant shadowed walls.
"That predecessor's meaning was clear: even if you awaken the Demon Mark… individual strength will still not be enough. We must wait until the day when all Hashira have achieved a second evolution and grown stronger through their marks. Only then, relying on the combined strength of the entire Corps… will we have even a single chance of success."
"This warning has been passed down and remembered by every Water Hashira generation since that predecessor passed away…"
____________________
For more advance chapters visit my patreon
patreon.com/kane45
Tier: 10$ Casual Reader - +20 Advance Chapter
20$ Intermediate Reader - +40 Advance Chapter
40$ Expert Reader - +80 Advance Chapter
Update: "Monday to Friday - Update 3 Chapters a Day"
"Saturday and Sunday - Off"