A few days later, at the Ubuyashiki clan's residence.
The Seven Pillars gathered once again.
When they heard that Kuno hadn't been able to recruit Oboro into the Demon Slayer Corps as he had hoped and that Oboro had only given him some books on breathing techniques, the reactions among the Pillars were varied: some were disappointed, some indifferent and some regretful.
Rengoku Tenjuro, with his distinctive fiery red and yellow hair and sword-like eyebrows, laughed heartily. "He didn't accept? What a shame! If a swordsman of his caliber joined the Demon Slayer Corps, he would undoubtedly shine brightly and inspire everyone!"
Kuno had deliberately prevented them from accompanying him to the meeting with Oboro.
This was partly out of courtesy, but more importantly, to protect Oboro.
If Muzan discovered someone with a new method of destroying demons' vitality, he would surely eliminate the threat immediately.
So it seemed best to keep the outside world in the dark about this person named Oboro.
"As our lord mentioned, Oboro doesn't have much time left. Even if he wanted to help us, I fear his contributions would be limited," said Kawai Ichimoku, the Water Pillar with short, neatly trimmed gray hair. He seemed to understand why Oboro had refused. "However, his innate talent for killing demons deserves further investigation."
"If it's neither a blade nor a breathing technique, what could it be? Perhaps a rare physical constitution that uses blood to destroy demon cells?"
Among the Demon Slayer Corps, some members possessed rare blood types that made them especially desirable to demons.
Certain rare blood types provided demons with the nutrition equivalent to ten or even a hundred ordinary humans, while the most exceptional ones had even higher nutritional value.
The blood of these individuals had a deadly attraction to demons and produced unique effects.
For example, just the smell of rich, sweet blood could cause weaker demons to experience momentary dizziness or mild physical paralysis.
This could be considered a form of mental stimulation.
However, no one had ever heard of blood that could destroy a demon's vitality.
"Breathing techniques have always been restricted to special groups like ours," someone added. "Without the mission of hunting demons, there's no reason or opportunity to learn these methods. His ancestors must have been members of the Demon Slayer Corps, or at least had some connection to the Corps. He could also be descended from an instructor."
But if they were the descendants of instructors, why wouldn't they join the Demon Slayer Corps? People like them had the sacred mission of killing demons.
"Every era has its complexities," said the Rock Pillar, a man with a square face, thick eyebrows, large eyes, and full lips. "Various factors intertwine to create change. Since he serves the Shogunate and is involved in national affairs, it's understandable that he might abandon his earlier, weaker convictions."
They couldn't call Oboro a traitor.
Demon slaying was dangerous, exhausting work that offered little reward compared to positions of power.
The best they could say was that the Oboro lineage's commitment to demon eradication hadn't been effectively passed down.
"Since he's been away from our 'team' for so long, whatever breathing techniques or swordsmanship he once knew must have become obsolete," said Guangzhu, the only woman among the Seven Pillars, her long ponytail swinging as she spoke dismissively.
Those who abandoned the path in the middle weren't worthy of being part of the Demon Slayer Corps. Such people should know better than to try to join now! Their respective breathing methods represented generations of refinement and adaptation through countless battles with demons. These techniques had evolved and grown stronger while Oboro's lineage had probably disappeared long ago. Under these circumstances, what value could his breathing methods have?
Kuno watched the seven pillars in silence, neither interrupting nor explaining.
After meeting Oboro personally and witnessing his unique qualities, he felt that some things didn't need to be explained and even if they were, the seven wouldn't accept them anyway.
He believed in Oboro anyway.
"Everyone, look at this!"
Suddenly, Fengzhu Masayuki spoke in a deep voice, his fingers trembling slightly as they gripped the book.
There was an unmistakable excitement in his tone.
He had been the first to pick up the book and read it, but he hadn't participated in the discussion.
He saw no reason to criticize Oboro.
The lord had only brought back some books, so all they had to do was find out if these books had any value. If not, the Demon Slayer Corps would continue as usual.
If they proved valuable, it would be a welcome bonus that would make the journey worthwhile.
"What is it?"
Noticing his expression, the others realized something significant and quickly divided the books among themselves and began to read.
The pages contained detailed illustrations of human meridians, with even the "acupoints" clearly marked. Annotations accompanied each body part and region, written in a comprehensive, accessible manner. Arrows indicated the pathways of "energy circulation.
For the first time, they learned that the "internal breath" formed by the breathing cycles produced remarkable effects.
All swordsmen knew that breathing strengthened the body, an effect magnified by "mental concentration," but none had encountered anything as detailed as these books. Most importantly, the text described how all the human meridians could form a complete "circuit. If one cultivated the internal respiration to its ultimate level, one's strength would increase beyond imagination.
Compared to the contents of the books, the Pillars' understanding of human physiology seemed elementary.
Oboro had given them a key to unlock the hidden treasures of humanity, revealing secrets they had never imagined.
"Internal breath essence, energy and spirit circulating through the body, it feels so mysterious."
After a long silence, Water Pillar Kawai Ichie licked his dry lips, somewhat confused.
Despite his knowledge of breathing, it was still difficult to fully comprehend the detailed illustrations.
"Is this really the breathing technique we know?"
"My book describes a method called static breathing with specific meridian pathways," said another pillar. "It also mentions that once the internal energy completes a small circulation, breathing becomes unrestricted, allowing one to sense external energy and harmonize inner and outer forces."
The other pillar swallowed hard and stared at his companion with wide eyes.
Was this really possible? The breathing techniques they knew only supported their bodies and temporarily generated combat power.
Breathing was exclusively human, how could it take form outside the body?
"My book deals with abdominal breathing. It seems simple, but"
The knowledge in these books was profound, but as Pillars with a solid foundation in breathing practice, they could still evaluate these methods.
Even though they didn't fully understand it, the practices described seemed undeniably feasible.
"Hahahahahahahaha!"
Suddenly, Flame Column Tenjuro burst out laughing. "How fascinating! Is it really as powerful as described? Only by practicing will we know!"
"Most of our breathing techniques depend on individual physical conditions and vary from person to person. Even Water Breathing, which I've mastered with generations of experience, is not easy to learn, but these books describe techniques without barriers that are suitable for everyone. Even someone who's missing body parts and can't complete the Great Circulation can try the Small Circulation."
The Water Pillar put down his book and looked at Kuno in surprise. "Who exactly is this person you met?"
"Our breathing methods are only for sword-fighting and demon-killing techniques, so they are relatively simple and crude. These methods, however, are complex and profound. They deal with life itself and aim to develop the body's infinite potential.
The elder Rock Pillar added, his voice shaking.
Unbelievable!
In fact, Kuno had already read these books upon his return.
Although he was not an expert in breathing techniques, he had sufficient knowledge. The "understanding of human potential" presented in these illustrations alone had shattered his existing concepts.
"Kibutsuji Muzan, his end is near!"
Ubuyashiki Kuno smiled serenely, gazing at the white clouds drifting across the sky as he spoke with unwavering conviction.
He couldn't help but clench his fists in determination.