Ubuyashiki Kagaya.
That was the name of the man who appeared before Riezel.
He was the head of the Ubuyashiki family as well as the 97th-generation leader of the Demon Slayer Corps.
Every member of the Demon Slayer Corps, whether they were the Hashira or ordinary members, held deep reverence and respect for their leader, as evidenced by how they addressed him as 'Master'.
Now, this leader was being supported by his wife and daughters, walking out of the mansion together, to a place where the sunlight could reach, standing opposite Riezel.
"Welcome to the headquarters of the Demon Slayer Corps, Tsugikuni Yoriichi."
Kagaya greeted Riezel with a gentle tone and a serene expression.
"I apologize for not being able to bow. As you can see, I am seriously ill and cannot make too many vigorous movements. Just walking out of the house like this has already drained most of my strength. I hope you can understand."
Although his voice was gentle, it carried a strong charisma, making people involuntarily feel a sense of trust toward him. Even Riezel, when facing him, couldn't help but slightly relax his usually calm expression.
"No need to be polite, Lord Ubuyashiki." Riezel shook his head. "I may have been invited, but I am just an ordinary guest, so don't bother with formality."
In this world, the Ubuyashiki family was an ancient family with a history of over a thousand years, extending from the Heian period to the present day, holding significant influence throughout the country.
This could be seen from the fact that they were able to establish a large organization like the Demon Slayer Corps without government support and have managed it almost single-handedly until this day.
Moreover, Riezel recalled from the original work that the salaries in the Demon Slayer Corps were quite generous; even the lowest-ranked Mizunoto could receive a monthly salary equivalent to about 200,000 yen in 2019, not to mention the salary of a Hashira.
Furthermore, all these salaries were paid by the Ubuyashiki family, along with expenses such as the treatment of injured members, post-demon battle cleanup, and expenses during mission execution, all of which were borne solely by this family.
Such a family undoubtedly possesses vast financial resources; otherwise, it would be impossible to independently manage a big organization like Demon Slayer Corps for nearly a thousand years.
Naturally, as the head of the Ubuyashiki family and the leader of the Demon Slayer Corps, Kagaya's status was extremely prestigious. In comparison, Riezel was just an ordinary young man and really didn't need any grand gestures.
"That being said, you are neither a member of the Demon Slayer Corps nor obligated to eradicate demons, yet you helped us defeat the Upper Three of the Twelve Kizuki. For this alone, we are deeply grateful."
Kagaya spoke softly to Riezel and shook his head slightly.
"Members of the Upper Ranks haven't changed for over a hundred years, which means that in all that time, no one has ever defeated an Upper Rank. On the contrary, we have lost countless Hashira to them."
As Kagaya's voice turned melancholic, it carried a tinge of sorrow.
It was a sorrow for the once sacrificial victim.
Every Hashira also hung their heads, their eyes clouded with gloom.
Twelve Kizuki, an organization composed of the highest and most powerful demons, had always been the bane of the Demon Slayer Corps, a constant thorn in their side.
Many Hashira had hunted Lower Ranks before; however, many had also perished at the hands of Upper Ranks.
Both the Demon Slayer Corps and the Twelve Kizuki were truly sworn enemies.
Once casualties occurred among the Lower Ranks of the Twelve Kizuki, they almost always fell to the Hashira of the Demon Slayer Corps. Likewise, if casualties occurred among the Hashira of the Demon Slayer Corps, they almost always fell to the Upper Ranks of the Twelve Kizuki.
They were nemesis locked in a cycle of mutual hunting, with the Hashira gaining fame by hunting Lower Ranks, and Upper Ranks earning their greatest merits by hunting the Hashira.
From Riezel's perspective, this was quite ironic.
After experiencing the event of the Mugen Train and successfully hunting both a Lower Rank and an Upper Rank, Riezel had roughly gauged the strength of demons and Demon Slayers.
Beginning with the weakest, a demon newly transformed, possessing diluted demon's blood, and not yet mastering the Blood Demon Art, was roughly equivalent to a Level 1 adventurer. They were stronger than ordinary humans but not entirely invincible against them.
Those who had mastered the Blood Demon Art, consumed humans, and gained some experience and strength were roughly equivalent to Level 2.
Lower Ranks were roughly equivalent to Level 3.
The Hashira and the Upper Ranks were roughly equivalent to Level 4.
However, the Upper Ranks generally surpassed the Hashira. If they had to be classified, most of the Hashira were akin to lower Level 4, while the Upper Ranks were at least upper Level 4.
Moreover, demons were naturally unafraid of death; whether their limbs were severed or their bodies pierced, as long as their heads weren't cut off by Nichirin Swords, they could immediately regenerate. With this advantage alone, they naturally held a significant edge over the Hashira when facing them.
Therefore, once someone in the Demon Slayer Corps reached the strength of a Hashira, they could easily slay Lower Ranks, earn merit, and become a Hashira. However, when facing the Upper Ranks, the Hashira often found themselves lacking in strength and were ultimately hunted down by them.
This led to the basic fact that the successive generations of Hashira had almost all perished at the hands of the Upper Ranks, leading to their deep hatred toward the Upper Ranks.
In fact, this was also the reason why the reaction of the Hashira was so big upon learning that Riezel had slain an Upper Rank.
On the other hand, since members of the Twelve Kizuki only met their demise at the hands of the Hashira, the Upper Ranks regarded them as enemies to be eliminated at all costs. Once confronted, they would never let the Hashira go.
Now, with Riezel having slain an Upper Rank for the Demon Slayer Corps, causing an absence in the Upper Ranks, which hadn't occurred in over a hundred years, this undoubtedly marked a monumental achievement for the Corps.
"Plus, with the Sun Breathing reemerging from you, I can already sense it. In our generation, Demon Slayers and demons may finally settle the score, putting an end to this millennia-old history of mistakes."
Kagaya's voice became somewhat energized as he spoke.
*Cough!* *Cough!*
However, due to the shift in his emotions, he suddenly started coughing violently.
"Master!"
"Please take care of yourself!"
Every Hashira was shocked one after another, speaking hastily as they saw Kagaya's wife and daughters supporting him by patting his chest and back to ease his discomfort.
"Don't worry, I'm fine... I'm just overwhelmed with happiness."
Kagaya reassured his wife and daughters, patting their hands, then gestured for everyone to relax before turning to Riezel with a smile.
"You truly live up to the name 'Tsugikuni Yoriichi'... Perhaps it's fate."
Hearing Kagaya's words, Riezel raised an eyebrow.
"You know Tsugikuni Yoriichi?"
"Of course..." Kagaya replied, looking deeply at Riezel's eyes.
"Tsugikuni Yoriichi, a swordsman born in the Sengoku era, was the first to master and create the breathing style."
"The Corps began practicing the breathing style under his guidance, giving us the ability to fight demons."
"However, the breathing style he created and used was said to be so powerful that it demanded strict requirements of the user's body, making it nearly impossible for anyone to learn it."
"As a result, various breathing styles were derived from the one he used."
Kagaya glanced at every Hashira kneeling in the courtyard as his voice slowly spread out.
"Water Breathing, Thunder Breathing, Flame Breathing, Stone Breathing, Wind Breathing—these are the five fundamental breathing styles. They are branches derived from Tsugikuni Yoriichi's breathing style."
"After the emergence of these five fundamental breathing styles, the Corps witnessed the rise of many talented individuals who developed derivative styles based on them."
"Love Breathing used by Love Hashira Kanroji Mitsuri is a derivative branch of Flame Breathing."
"Insect Breathing used by Insect Hashira Kochou Shinobu and Serpent Breathing used by Serpent Hashira Iguro Obanai are derivative branches of Water Breathing."
"Sound Breathing used by Sound Hashira Uzui Tengen is a derivative branch of Thunder Breathing."
"Mist Breathing used by Mist Hashira Tokitou Muichirou is a derivative branch of Wind Breathing."
"In this way, various breathing styles emerged successively, but the breathing style of Tsugikuni Yoriichi, which served as the origin of all these breathing styles, has been lost."
As Kagaya spoke, a rich smile appeared on his face involuntarily.
"Until my generation, the origin of all breathing styles—the ancestor and foundation of them all—has finally been revived in the world once again."
Upon hearing that, everyone couldn't help but wonder what Kagaya meant.
"Could it be... the Sun Breathing this boy used is the breathing style Master was talking about?"
Sanemi couldn't help but speak up in shock.
Upon hearing him, the other Hashira cast astonished looks at Riezel one after another, surprised by this sudden revelation.
"Master!" Kyoujurou exclaimed surprisedly. "Why were we not informed of such an important matter?"
Indeed, whether it was Sun Breathing or Tsugikuni Yoriichi, hardly any Hashira present knew of their existence.
This was very absurd.
Sun Breathing was the origin and foundation of all breathing styles, the strongest breathing style, while Tsugikuni Yoriichi was the one who created this breathing style, bringing it to the world.
Why were such important matters devoid of any records or tales within the Demon Slayer Corps?
"The reason is simple..."
Riezel spoke up, answering Kyoujurou's question.
"Because Tsugikuni Yoriichi once made some mistakes and got banished from the Corps. On top of that, the legacy and records about Sun Breathing were brutally destroyed. That's why there are hardly any records about these two within the Corps."
Riezel's explanation shook everyone.
"That's right..."
Kagaya sighed resignedly and lowered his head.
"I must say, it's a very tragic situation."