This is more than just the potential to become a Hashira!
Morioka Nen had been with the Demon Slayer Corps for nearly sixty years. Though he had retired due to injuries years ago, he had never seen anything like this in all that time.
He had heard rumors recently—quite exaggerated ones.
And the young man before him seemed not far off from those tales.
"I heard recently that the new Mist Hashira went from being an ordinary person who had never held a sword to a Hashira who slew a Lower Moon demon in just two months. I didn't quite believe it at the time, but seeing you now, I realize it's true. There really are such geniuses in this world," the old monk sighed.
"Master Morioka, you flatter me," Hardy replied, shaking his head.
Compared to his main body and his DC incarnation, he was hardly a genius at all.
So, Hardy picked up the bamboo sword and tried again.
With the memories from his DC incarnation as a foundation, his performance this time was even better than before.
Morioka Nen sighed again.
Such obvious progress—if this isn't genius, what is?
...
...
It only took Hardy three days to master all the forms of Breath of the Wind.
Within a month, relying on his incarnations in two worlds, he had refined Total Concentration Breathing of the Wind to a considerable level.
When combining chakra with the breathing technique, Hardy could fight Morioka Nen to a draw for three moves—because the latter, at full strength, could only manage three moves.
According to Morioka Nen, those three moves were about seventy percent as powerful as his peak.
Hardy was fairly satisfied with his current strength.
This body had only been training with chakra for a short time, and combined with the newly learned breathing technique, he already had about seventy percent the strength of an A-rank swordsman—making him a high-level fighter just below Hashira in the Demon Slayer Corps.
All that was left was to continue training chakra, have his other incarnations in the two worlds study Breath of the Wind in depth, and share the experience.
Relying solely on the experiences of his main body and DC incarnation was not enough; he needed sufficient training to digest those experiences and develop muscle memory.
At most, this would bring him close to the level of his main body or DC incarnation. To surpass them wasn't impossible, but while he here would need long, hard training to make further progress, the other two bodies, with their innate talents, might reach that step in much less time.
Hardy's next goal in the Demon Slayer world was to fully integrate the techniques of Breath of the Wind, improve his swordsmanship, and strengthen his body to better support the breathing technique.
He aimed to maintain Total Concentration Breathing at all times—sitting, standing, walking, even sleeping, breathing continuously for twenty-four hours a day.
This state is called Total Concentration: Constant, and it places high demands on one's cardiovascular and overall physical fitness.
For ordinary swordsmen aspiring to reach Hashira-level strength, mastering Total Concentration: Constant is the best method.
Basically, all A-rank swordsmen in the Demon Slayer Corps have mastered this technique.
Aside from Total Concentration—
Apart from the basics, Morioka Nen had nothing more to teach Hardy.
It was time to say goodbye.
"Master Morioka, thank you for your patient guidance these past days."
At the entrance of Ritsuzan Temple, Hardy, carrying his pack, bowed with a Buddhist salute to Morioka Nen.
"Amitabha. Hardy-kun, you are exceptionally gifted. This old monk is nothing but a gray-bearded relic nearing the end of his journey, with little left to teach. I only hope you achieve great success in the selection at Fujikasane Mountain a month from now, and then go on to slay demons and protect the people."
The old monk pressed his palms together and recited a Buddhist blessing for Hardy.
"Oh, by the way, this is a small offering for incense. Please, Master, do not refuse."
Hardy took a small cheque from his pocket.
This was a kind of check used during the Meiji and Taisho eras.
"This... is too much,"
Morioka Nen glanced at the amount on the cheque and waved his hands repeatedly.
"It's fine, really. As you know, my family is quite well-off. This is just my pocket money for a month. I've noticed that Ritsuzan Temple's buildings are quite old and in need of repairs. You need this money more than I do."
Hardy pressed the cheque into Morioka Nen's hand and patted his own chest reassuringly.
His branch of the Uesugi family held considerable influence in the Koka region—calling themselves "half the city of Uesugi" would not be an exaggeration. Their assets were substantial.
Before Morioka Nen could reply, Hardy continued,
"By the way, I'd like to ask you about the area the Water Hashira usually oversees."
"The Water Hashira?"
Morioka Nen was a bit curious, but still gave a general description.
"I thought you said you were going to learn Thunder Breathing? Why are you looking for the Water Hashira? If you wish to learn Water Breathing, I suggest you visit Sagiri Mountain and seek out the former Water Hashira, Sakonji Urokodaki."
"Does this Mr. Urokodaki still take disciples?"
Morioka Nen wasn't sure why Hardy was asking, but answered anyway:
"Among Mr. Urokodaki's disciples, aside from the current Water Hashira, Giyu Tomioka, none have survived. Since his last disciple died in the Fujikasane Mountain trial a few years ago, he hasn't taken any new students for six years now."
"I understand. Thank you, Master Morioka. I'll take my leave now."
Hardy bowed once more and turned to go.
The fact that Urokodaki Sakonji currently had no disciples meant that the protagonist, Tanjiro Kamado, and his family had not yet met their tragedy, nor had they been rescued by Tomioka Giyu and sent to Sagiri Mountain for training.
"Breath of the Sun... Hinokami Kagura..."
Hardy took out the map he'd brought from home and spread it out, muttering to himself.
With the abilities of his true self and his DC avatar, he could easily master Wind Breathing, and Thunder Breathing likely wouldn't be difficult either. But he wasn't sure if he was compatible with the Breath of the Sun—not being a so-called "child of the sun."
Neither Hardy of this world nor his true self had any ancestors in the past three generations who worked in fire-related trades, nor did they have red hair or red eyes.
Still, the Breath of the Sun was the strongest and original breathing technique. Hardy would not be satisfied without at least trying to learn it.
The Kamado family's location was uncertain. Hardy could only search for suitable places within the area usually overseen by the Water Hashira—remote mountains, with a small town at the foot of the mountain where Tanjiro often went to sell charcoal.
"It's best to make use of the family's influence."
Hardy oriented himself and set off toward the Koka City area.
Before coming here, he had asked his third uncle, Uesugi Yuu, to purchase a batch of materials for him.
These were for making puppets.
Even though the world's industrialization was still relatively backward, and unlike the Naruto world there weren't many chakra-compatible materials, the puppets he made here wouldn't be extremely powerful. Still, they could somewhat enhance his combat ability.