Tanjiro and the others were preparing to leave, and naturally, Inosuke could not remain inside a den filled with demons. He had to return with the Demon Slayer Corps.
The most pressing matter now was Kotoha's future. Now that mother and son had finally reunited, Inosuke would never allow his mother to continue living among demons.
Kotoha, however, found herself torn. She did not want to leave Doma, yet she also wished to spend more time with the son she had thought she had lost forever.
In the end, it was Doma himself who proposed a solution.
"Kotoha, stay with Inosuke for a few days. I'll come and bring you back afterward."
Most humans and even most demons would assume Doma was simply carefree and immature, but beneath that seemingly frivolous smile, he had considered everything carefully.
First, Muzan would undoubtedly learn about everything that had happened tonight. If Kotoha remained beside him, there was a real possibility she would become involved.
With the Demon Slayer Corps, however, she would be much safer.
Besides…
Kokushibo was there.
As long as Kokushibo was involved, Doma believed nothing unexpected would happen.
Thus, Tanjiro, Tengen, Zenitsu, Muichiro, Inosuke, and Kotoha departed without a single clash.
At that very moment…
A familiar voice echoed directly inside every demon's mind.
"Return. All of you."
It was Muzan's command.
Without hesitation, every member of the Twelve Kizuki withdrew from Yoshiwara and returned to the Infinity Castle.
The Infinity Castle.
Muzan Kibutsuji stood at the center of the great hall, looking down upon the assembled Twelve Kizuki.
Her crimson eyes settled on Kokushibo.
"Kokushibo."
"This time… you owe me an explanation."
Her voice was colder than anyone present had ever heard.
"You adopted the Flame Hashira as your son."
"You are the ancestor of the Mist Hashira."
"You have repeatedly allowed members of the Demon Slayer Corps to escape."
"And now… even the child you once rescued has become a Demon Slayer."
She slowly descended the stairs.
"Tell me…"
"Are you planning to stand with the Demon Slayer Corps… and kill me?"
Although her tone remained icy, every demon present could detect something hidden beneath it.
Disappointment.
Confusion.
Even… hurt.
Now that everything had been exposed, Kokushibo no longer saw any reason to conceal the truth.
"Lord Muzan."
"You misunderstand me."
"I have never betrayed you."
"Everything I have done has been for a single purpose…"
"To discover a method that allows demons to conquer the sun."
Those words only made Muzan's expression darken further.
"The sun…"
Immediately, she recalled the mission she had entrusted to Kokushibo countless years ago.
Then another thought surfaced.
Just like Tamayo…
Kokushibo had somehow escaped the absolute control of her blood.
"I knew it…"
Her voice became even colder.
"You broke free from my control."
"Just like Tamayo."
"It seems the two of you truly are connected."
The instant those words fell
Her right arm expanded into a grotesque mass of flesh, dozens of bladed tendrils exploding toward Kokushibo.
Without hesitation
Moon Breathing.
First Form: Dark Moon Evening Palace.
The crescent-shaped slash erupted instantly, shattering every incoming appendage before they could reach him.
The hall fell silent.
Muzan herself appeared directly before Kokushibo.
Her crimson eyes stared into his six.
"You truly believe…"
"I wouldn't kill you?"
The command was issued immediately.
Every member of the Twelve Kizuki received Muzan's order simultaneously.
Surround Kokushibo.
Kill him.
Although fear filled every demon's heart, none dared disobey.
They slowly closed in.
Fortunately for Kokushibo…
Akaza stepped beside him without hesitation.
Having also broken free from Muzan's complete control, Akaza naturally chose Kokushibo's side.
The atmosphere instantly became tense.
"Lord Muzan…"
Kokushibo sighed softly.
"Does it truly have to come to this?"
"What else should I do?"
Muzan replied coldly.
"Wait until you lead the Demon Slayer Corps here to kill me?"
The demons prepared to attack.
But Kokushibo remained perfectly calm.
Then he spoke one sentence.
"I have found a method for demons to conquer the sunlight…"
"…without the Blue Spider Lily."
Silence.
Complete silence.
Every demon froze.
Even Muzan's pupils contracted.
For over a thousand years…
Everything she had pursued existed solely for that dream.
To walk beneath the sun.
And now
Kokushibo claimed he had found another path.
After several long moments, Muzan finally suppressed the storm within her heart.
"So?"
She asked coldly.
"Would you actually tell me?"
The killing intent filling the Infinity Castle weakened ever so slightly.
Kokushibo immediately recognized the opportunity.
Without another word, he sheathed his Nichirin katana and handed it to Akaza.
Then…
He calmly walked toward Muzan.
Lower Moon demons instinctively moved to block his path.
But before Kokushibo even reached them, they silently stepped aside.
No one wished to become an obstacle.
No one wanted to test the strength of Upper Rank One.
Kokushibo finally stopped before Muzan.
Neither of them spoke.
Their eyes simply met.
The rest of the demons scarcely dared to breathe.
Far away, Nakime quietly observed everything while resting her hands upon her biwa.
Beside her, Kyogai gripped a brush in one hand and paper in the other, determined to record this historic scene.
Yet…
No words seemed capable of describing what unfolded next.
Without warning
Kokushibo stepped forward and gently pulled Muzan into his embrace.
The entire Infinity Castle froze.
Every demon stood rooted in place.
Nakime's eyes widened.
Kyogai's brush slipped from his fingers.
Even Akaza's usually expressionless face stiffened.
Doma covered his mouth to suppress his laughter.
No one had imagined…
That Kokushibo would actually dare.
Muzan herself froze completely.
Shock.
Confusion.
Embarrassment.
A thousand unfamiliar emotions flashed across her face.
She herself could not understand them.
Once, she had been a being who viewed every living thing as insignificant.
But ever since Kokushibo had entered her endless existence…
Something had slowly begun to change.
Those changes existed for only one person.
Kokushibo lowered his voice.
"Lord Muzan…"
"Believe me."
"We will conquer the sun."
Muzan looked up into those six unwavering eyes.
She wanted to question him.
She wanted to reject him.
Yet…
No words came out.
After a long silence, she finally spoke.
"…One last time."
"I'll believe you."
That single sentence carried every emotion she had been unable to express.
She gently pushed Kokushibo away.
Her usually composed expression had become noticeably unnatural.
"Nakime."
"Take me back."
Nakime immediately bowed.
"At once, Lord Muzan."
With a single strum of her biwa, the Infinity Castle shifted, and Muzan disappeared from the hall.
Only after Muzan had completely left did every demon finally release the breath they had been holding.
Thank goodness…
No one had wanted to fight Kokushibo.
Especially the Lower Rank demons.
Against Upper Rank One, they would not survive even a single exchange.
Seeing Kokushibo standing silently, his shoulders trembling ever so slightly, Doma walked over with his usual smile and gave him a hearty slap on the back.
"Congratulations, Lord Kokushibo."
"Congratulations?"
Kokushibo let out a bitter laugh.
Only he knew how dangerous that moment had truly been.
Had he failed to convince Muzan…
She would have hunted him to the ends of the earth.
And Nakime, absolutely loyal to Muzan, would have expelled him from the Infinity Castle the moment dawn approached.
There would have been nowhere left for him to hide.
Fortunately…
This Muzan was no longer the utterly heartless Demon King she had once been.
At least…
Not when it came to him.
While the Infinity Castle slowly returned to calm…
The atmosphere within the Wisteria House remained equally complicated.
Kotoha scarcely took her eyes off Inosuke, as though afraid he would disappear again if she looked away for even a moment.
Everyone listened quietly as she recounted everything that had happened over the past decade.
The room gradually fell silent.
Tanjiro frowned thoughtfully.
"My godfather… Great-Grandfather Kokushibo…"
"He really isn't an ordinary demon."
Tengen crossed his arms.
"What exactly is Upper Rank One trying to accomplish?"
No one could answer.
Even Tamayo remained deep in thought.
At that moment, Nezuko quietly approached Kotoha.
Seeing the gentle woman whose face resembled Inosuke's so closely, she couldn't help but move nearer.
Kotoha smiled warmly and gently stroked Nezuko's head.
"So you're a demon too?"
Her smile became even softer.
"What a kind child you are."