Night had fallen on Mount Kumotori, in front of Tanjuro's house.
Tanjuro was dressed in the ceremonial robes he only wore for rituals.
He was circling the bonfire, holding a wooden ritual implement as he tirelessly repeated twelve movements, over and over without end.
Kujo Tachibana sat quietly to one side, holding Iron-Head Kid Tanjiro, who was only seven or eight years old.
"Tanjiro, watch closely."
"Pay attention to how your father breathes."
Iron-Head Kid Tanjiro nodded earnestly.
"I'll make sure I learn, Tanjiro will."
"Once Tanjiro learns, Father won't have to work so hard. Tanjiro can take his place."
Kujo Tachibana smiled, then focused again, carefully sensing the changes in Tanjuro's body and the way he breathed.
This was the first time Tachibana had truly witnessed the power of Sun Breathing!
It truly lived up to being that man's exclusive Breathing Style. To Kujo Tachibana's senses, Tanjuro seemed to become one with himself, no longer a person but a blazing fireball.
Every inch of his flesh moved gently in time with the rhythm of his breathing!
This wondrous Breathing Style naturally stirred the power hidden within the human body.
In Kujo Tachibana's eyes, the twelve movements of Hinokami Kagura were no longer merely sword forms.
Instead, they seemed like movements the body naturally displayed in response to this Breathing Style!
So that was it! That was it!
No wonder that man's Breathing Style was so powerful!
Kujo Tachibana felt as though he had found the answer he'd been looking for.
The human body itself contained endless mysteries.
What he needed to do now wasn't deliberately pursue some special breathing method. He needed to carefully sense and listen to his own body.
His body had already given him the answer!
At that moment, Kujo Tachibana thought of that man again.
Right—that was probably one of the reasons Yoriichi Tsugikuni had been so strong from birth.
Because he had been born with Transparent World, even as an infant, before he had developed self-awareness, his body's instincts had driven him to keep adjusting the way he breathed.
Until that infant, born with Transparent World, had unconsciously developed a way of breathing best suited to his own body!
(I think my deduction is pretty cool. This must be how it happened.)
Of course, Sun Breathing being best suited to Yoriichi's body didn't mean no one else could use it.
After all, Breathing Styles were, at their core, simply a way to strengthen the human body.
That was probably why Yoriichi had been able to derive the five foundational Breathing Styles from Sun Breathing!
Kujo Tachibana relaxed his body and opened every pore. He drew in a long breath to calm his excitement.
Once his mind had settled, Kujo Tachibana let his perception and consciousness sink completely into his body.
He sensed the feedback from every part of his body as he practiced Body Breathing: the joy of his cells... the rumbling of his muscles... the strain on his bones and sinews...
In this way, Kujo Tachibana used the subtle feedback from within his body to continually adjust the frequency and rhythm of the breathing through his pores...
But before Kujo Tachibana had gotten very far with his work, something unexpected happened the next moment.
Kujo Tachibana's head tilted to one side, and he fell asleep.
The next morning, Kujo Tachibana finally stirred awake.
"Father, Uncle Kujo's awake!" Iron-Head Kid Tanjiro shouted to Tanjuro outside.
Before long, Tanjuro came in and asked Kujo Tachibana, "Are you all right? You gave Tanjiro quite a scare last night."
Kujo Tachibana looked at Tanjiro and smiled. "I'm fine. Thank you, Tanjiro."
He checked how he felt, but there was no discomfort. As for what had happened the previous night, Kujo Tachibana had a pretty good idea of the cause.
He had probably fainted because of a condition called "oxygen intoxication."
On the Blue Star of his previous life, oxygen intoxication was explained as a reaction that occurred when the body, having adapted to the low-oxygen environment of a high-altitude region, re-entered an area with a relatively normal oxygen level.
It could cause fatigue, weakness, drowsiness, chest tightness, dizziness, and even diarrhea—a reaction known as "de-adaptation" or "low-altitude sickness."
Kujo Tachibana had developed these symptoms because he had opened every pore the previous night to sense how his body responded to breathing through them.
It was the first time he had ever breathed so freely!
But that very act had set off a chain reaction.
A large amount of oxygen had entered his blood. Without a Breathing Style to convert it, he could only suffer the awkward symptoms of oxygen intoxication.
At that thought, Kujo Tachibana realized he might have to change his plans.
He had already suspected Sun Breathing would bring him a pleasant surprise, but he hadn't expected it to be such a big one.
Just from the inspiration Sun Breathing had given him, he had already found his direction. Now all he had to do was keep moving forward.
His own unique Breathing Style was waiting for him up ahead.
All he had to do now was lie low for a while, until the day he broke free of his cocoon. When that day came, the whole world would change because of him!
Kujo Tachibana wasn't in a position to keep wandering around outside, and oxygen intoxication was a serious problem. If he continued researching his Breathing Style out there, it could be dangerous.
So Kujo Tachibana, who had only recently left the Demon Slayer Corps Headquarters, had decided to return there with the Kamado Family.
Before leaving, however, he had one important thing to do.
Kujo Tachibana got up from the tatami, got dressed, washed up, and then had breakfast at Tanjiro's house.
Since he had arrived, the Kamado Family's meals had visibly improved over the past few days.
As the Rumble Hashira of the Demon Slayer Corps, Kujo Tachibana certainly wasn't short of money.
Apart from food, he had little to spend it on. Buying some high-quality ingredients for the Kamado Family was a trivial matter to him.
For Tanjuro, though, it was a problem that had gone unresolved for years...
Seeing the happiness on his children's faces, Tanjuro and his wife, Kie, felt a little embarrassed, but they didn't refuse Kujo Tachibana's kindness.
After breakfast, the Kamado Family bustled about, packing the things they would take with them.
Tanjuro didn't know whether he should be happy or sad.
When it came to moving away from Mount Kumotori, he had unexpectedly realized that his family didn't seem nearly as opposed to the idea as he'd imagined...
"Tanjiro, come over here for a moment." Kujo Tachibana beckoned Iron-Head Kid over.
"What is it, Uncle Kujo?" Iron-Head Kid trotted over eagerly.
Kujo Tachibana thought for a moment, then asked, "Is there a kind of blue flower near your house?"
"This blue flower only blooms during the day for two or three days each year."
Before you continue