The Butterfly Mansion was bustling with activity today as Kakushi members hurried back and forth, carrying supplies.
In a corner of the courtyard, a makeshift shed had been erected.
The forge was already built, and the anvil had been brought over.
Although he was joining the Demon Slayer Corps, Sosuke had no intention of abandoning his identity as a swordsmith.
Whether it was Kagaya's wishes or his own pursuit of greater strength, forging Nichirin Blades remained essential.
Therefore, the swordsmithing shed was still necessary.
However, considering that the Butterfly mansion frequently housed injured Demon Slayer Corps members, Sosuke's shed was located in a secluded and quiet corner to avoid disturbing their recovery.
He sat on the side, watching the Kakushi bustle about while reading a letter.
The letter was from Tecchin, reminding Sosuke not to forget his identity and responsibilities as a swordsmith. Even if he learned sword techniques and eventually became a member of the Demon Slayer Corps, he must never forget his crucial duty of forging Nichirin Blades.
The letter also inquired about the Nichirin Blade he had crafted for Kanae.
What special techniques had he used to imbue the blade with its demon-suppressing power?
Sosuke had expected Kagaya to ask this question, but he was surprised to receive the inquiry from Tecchin instead.
He had been planning to visit the Swordsmith Village to explain his situation before formally beginning his sword technique training.
However, the letter instructed Sosuke not to return to the village, and forbade him from wearing the Mask during his training and even after becoming a member of the Demon Slayer Corps.
These revelations gave Sosuke a strange feeling.
"I have a feeling they don't just want me to become a Demon Slayer Corps member..."
Unable to unravel the complexities of the situation immediately, he decided to set aside his pondering and instead focus on drafting a reply to Tecchin.
Turning back into the house, he picked up paper and brush. The brush tip moved slightly, first writing the customary greetings, then adding promises not to neglect his duties. After a moment's hesitation, he wrote:
"Regarding the forging of Nichirin Blades, it originated from a forging method I stumbled upon, one that merges Breathing Techniques with forging techniques. The Village Chief may recall the accident I had on the mountain before this—it was during that incident that I obtained this legacy. The original text was damaged by a trap, so I've extracted a portion of the contents and included it as an attachment. Please have the Village Chief carefully select young swordsmiths from the village to attempt this method and see if they can forge Nichirin Blades capable of suppressing demons, just as I have."
At this point, Sosuke paused briefly before continuing to write: "When practicing the Breathing Technique, please do not push yourself too hard. If any unexpected issues arise, stop immediately and seek guidance from an experienced swordsman. If you have any questions that require my clarification, Village Chief, feel free to send me a letter or wait until I return to the village to answer them in person."
He let out a small breath, then extracted a small portion of Sun Breathing and wrote it down on a separate sheet of paper, labeling it the "Gale Sun Hammer."
This decision was the result of Sosuke's careful deliberation.
The matter of the Breathing Technique couldn't be completely concealed. Shinobu and Kanae had both witnessed it firsthand. It was impossible for a normal swordsmith to wield a hammer with such speed and power under those circumstances.
Therefore, attributing this ability to the incident in the mountains and providing a detailed explanation served as a plausible explanation for how a mere swordsmith could exhibit such extraordinary capabilities.
Secondly, by extracting a portion of the Breathing Technique and having them experiment with it, they could potentially provide the Demon Slayer Corps with a large number of Nichirin Blades capable of suppressing Demon regeneration.
If successful, the Demon Slayer Corps' combat power would undoubtedly increase dramatically, something Sosuke was extremely eager to see!
Conversely, even if they failed, this partial technique could still enhance the physical capabilities of the Swordsmiths in the village to some extent.
Of course, all of this depended on whether they could successfully utilize the technique.
As he pondered this, his eyebrows suddenly twitched. "Ultimately, it's still uncertain whether they'll even be willing to try. The Swordsmiths of Swordsmith Village are extraordinarily devoted to their craft. Hmm, but perhaps... for the sake of forging even better Nichirin Blades, they might be willing to experiment?"
He neatly folded the letter and slipped it into an envelope.
Leaning back slightly to ease his back, his mind drifted to another question.
In the past thousand years, had no one truly attempted to integrate Breathing Techniques into forging?
Unlikely.
However, the Sun Breathing technique had long been lost, and the various derivative Breathing Techniques might not amplify the Nichirin Blade accordingly.
But if it truly existed, at least a corresponding attribute should have emerged.
He frowned, suddenly feeling that the chances of success were slim.
'Could it be that the emergence of the Yang Flame Attribute depends not only on Sun Breathing, but also on the corrections from my Golden Finger?'
This question still required verification to find the answer.
Moreover, Sosuke hadn't revealed the complete Sun Breathing technique for two reasons: first, he needed feedback from this initial attempt; second... it was a touch of selfishness in his character.
'In any case, what I've provided should be enough for them to manifest Gale Sun. If it fails, this matter ends here.'
Calming his thoughts, Sosuke handed the letter to Kanae, instructing her to send it to the Swordsmith Village through their channels.
Though he wished to spend more time with Kanae, he returned to his own courtyard, mindful of the Kakushi's duties.
Seizing the moment is important, but long-term gains are even more crucial.
Just as Sosuke returned to his courtyard, he discovered an uninvited guest.
The figure lay sprawled on a tree branch, head tilted downward, bandages wrapped around their face. Yet their eyes were strikingly different colors: golden right eye, green left eye. Mid-length hair drifted loosely, and a small white snake perched on their shoulder, flicking its tongue as it stared at Tetsu no Sosuke.
The Serpent Pillar—Iguro Obanai!
Sosuke froze for a moment, but before he could react, Obanai flipped off the branch and landed lightly on the ground.
"I want to commission a Nichirin Blade from you!" Obanai declared bluntly, then asked, "You're Sosuke, right?"
Sosuke was momentarily speechless. 'To make such a request without even confirming my identity... is that really appropriate?'
He could only ask, "I can do that, but may I ask who you are?"