Muzan Kibutsuji had become completely obsessed with researching the Monjushiro.
At this point, he practically wished he could grow another brain solely for experimentation.
As for the demons beneath him?
He temporarily postponed any strict investigation. In Muzan's view, none of them would dare conceal information from him anyway.
Unfortunately
What Muzan never expected was that by the time he finally remembered to investigate properly…
…it would already be too late.
Watching Muzan devote himself entirely to research, both Kokushibo and Nakime silently admired him.
"Lord Muzan is truly dedicated to overcoming the sun," Nakime said softly.
Kokushibo folded his arms.
"He is merely a thousand-year-old demon who wishes to stand beneath sunlight."
"What crime has he committed?"
His tone sounded genuinely indignant.
Then another thought quietly surfaced in Kokushibo's mind.
"She only wanted to wear a swimsuit and relax on a beach beneath the sunlight."
"What crime has she committed?"
Naturally
He wisely chose not to say that aloud.
Meanwhile, far from the Infinity Castle, the four Hashira slowly traveled back toward Demon Slayer Corps headquarters.
Tengen Uzui and Giyu Tomioka remained strangely silent the entire journey.
Not because they wished to
But because the poison still lingering in their bodies had partially numbed their tongues.
Muichiro carried Giyu on his back despite being only thirteen years old himself.
Thankfully, Giyu's lean build made him relatively easy to support.
As for Mitsuri
She effortlessly carried the far heavier Tengen as though his weight meant nothing at all.
Her monstrous muscle density truly defied common sense.
Along the road, they encountered several Kakushi squads and Corps support personnel who had rushed toward Shizuoka after receiving emergency reports.
Tengen immediately warned them.
"Do not head toward Shizuoka yet."
"Those Upper Rank demons may still be nearby."
Thus, the rescue squads quickly changed course and instead escorted the injured Hashira directly toward the Butterfly Mansion.
Fortunately, Tengen's body retained considerable poison resistance thanks to the brutal shinobi training of the Uzui clan.
His condition, while serious, remained manageable.
Giyu's situation was stranger.
The poison previously introduced into his body by the Monjushiro had unintentionally slowed the spread of Gyokko's toxins.
Ironically
One poison had partially suppressed another.
Because this marked Kagaya Ubuyashiki's first direct clash against Upper Rank demons since becoming the Corps leader, he personally traveled to the Butterfly Mansion despite his deteriorating condition.
Supported gently by one of his daughters, Kagaya entered the recovery room.
On the beds, Giyu, Tengen, and Muichiro remained unable to stand properly.
Only Mitsuri remained healthy enough to greet Kagaya respectfully.
The others could not help but wonder:
How was Mitsuri somehow the least injured among them?
After hearing the full report involving Upper Rank Four and Upper Rank Five, Kagaya himself felt chills run down his spine.
If Kokushibo had not intervened unexpectedly
The Demon Slayer Corps might have lost four Hashira in a single night.
Still, one particular detail caught his attention.
"Muichiro…"
"You are truly a descendant of Upper Rank One?"
"Yes," Muichiro answered honestly.
After all, that bloodline connection had undeniably saved their lives.
If the Demon Slayer Corps chose to expel him because of it
He would not complain.
But Kagaya merely smiled gently and changed the subject.
"To think Upper Rank Four possesses such terrifying abilities…"
"Even four Hashira struggled against him."
Tengen lowered his head slightly.
"I apologize, Oyakata-sama."
"We failed to defeat them."
Kagaya shook his head softly.
Even through the curse spreading across his face, his expression remained calm and warm.
"No."
"The fact that all of you survived is already miraculous."
"The Demon Slayer Corps will remember this debt."
At that moment, two more Hashira arrived at the Butterfly Mansion.
The Wind Hashira, Sanemi Shinazugawa.
And the Serpent Hashira, Obanai Iguro.
However
They were carrying someone severely injured between them.
"Brother?!"
Muichiro's eyes widened instantly.
Lying unconscious before him was Yuichiro Tokito.
Seeing Mitsuri unharmed, Obanai quietly relaxed.
Meanwhile, Sanemi unceremoniously dropped Yuichiro onto an empty bed before ordering Shinobu to treat him immediately.
Then he turned sharply toward Muichiro and grabbed him by the collar.
"You brat."
"You knew from the beginning that you were related to Upper Rank One, didn't you?"
"Why did you hide it from everyone?"
The room instantly fell silent.
Even Mitsuri looked shocked.
Muichiro frowned slightly before gripping Sanemi's wrist firmly.
"Yes."
"But first tell me why my brother is injured."
Sanemi felt the frightening strength hidden within Muichiro's smaller frame and clicked his tongue internally.
Truly
That monster's bloodline was no joke.
Seeing tension rising, Kagaya immediately intervened.
"Sanemi. Muichiro."
"Both of you, let go."
Only after they released each other did Kagaya calmly explain the situation.
Earlier, Kasugai Crows had reported Monjushiro sightings near Mount Keishin.
Because the number of creatures remained unknown, Kagaya dispatched two Hashira as a precaution:
Sanemi Shinazugawa and Obanai Iguro.
When they arrived
They discovered someone already fighting the Monjushiro alone.
Yuichiro Tokito.
Using nothing more than an ordinary blade left behind by Muichiro, Yuichiro had protected nearby villagers despite lacking formal training.
More shocking still
He had unconsciously used Mist Breathing techniques.
Mist Breathing, Second Form: Eight-Layered Mist.
Even Sanemi and Obanai had been stunned by his natural talent.
However, after the battle ended, Obanai openly declared that all demons and Monjushiro were disgusting creatures that deserved extermination.
Those words instantly enraged Yuichiro.
After all
He would never tolerate anyone insulting the great-grandfather he respected deeply.
Though Yuichiro attempted to hide his reaction, the two Hashira immediately noticed something suspicious.
Eventually, Sanemi knocked him unconscious and brought him back for questioning.
"You entire Tokito family hid information about Upper Rank One for years," Sanemi growled.
Yuichiro looked slightly helpless.
Truthfully
He had simply forgotten to tell Muichiro not to reveal too much.
Still, he did not blame his younger brother.
If someone insulted their great-grandfather in front of him, he would have reacted exactly the same way.
After hearing how Kokushibo spared the four Hashira personally, even Sanemi no longer knew what to think.
Kagaya spoke gently once more.
"The Demon Slayer Corps must remain united."
At that moment, Muichiro slowly sat upright in bed despite his injuries.
Then he bowed deeply toward everyone present.
"I'm sorry for hiding this for so long."
"But Great-Grandfather never asked us to betray the Demon Slayer Corps."
Kagaya nodded immediately.
"I believe you, Muichiro."
Sanemi clicked his tongue irritably before finally muttering,
"…Sorry."
"I shouldn't have assumed you were our enemy."
Thus, the conflict was resolved for the time being.
Later, after Yuichiro regained consciousness, the brothers quietly discussed everything together.
Watching them speak beside one another
Shinobu Kocho unconsciously revealed a trace of envy in her eyes.
"Elder sister…"
For a moment, her thoughts drifted elsewhere entirely.
And because of that distraction
She completely failed to notice her hands moving while treating Giyu's injuries.
The ointment she had been applying to his face somehow migrated lower and lower…
Until eventually
Her hands ended up directly on Giyu's exposed abdominal muscles.
"Shinobu!"
Mitsuri's face instantly turned bright red.
"S-Stop that!"
"This is incredibly inappropriate!"
Startled back to reality, Shinobu blinked blankly.
"Hm? What happened?"
Then she looked down.
Silence.
Immediately afterward, Shinobu retracted her hands at lightning speed, her face turning scarlet.
Though before withdrawing
She instinctively gave his abs one final pat.
Well.
At least she got something out of the misunderstanding.
After an entire day of travel, Tanjiro and Inosuke finally arrived near Sakonji Urokodaki's residence by evening.
"Inosuke, look!"
Tanjiro pointed excitedly toward the small house ahead.
"That's Urokodaki-sensei's home!"
"FOOD!"
Inosuke's eyes lit up instantly as though lightning had struck him.
"Move, Tanjiro!"
"I'm starving!"
The two rushed toward the house energetically.
But just as they approached
BANG!
The front door exploded open from the inside with a violent kick.