Naruto: Blade of the Sharingan

"In the beginning, you must firmly remember the movements and sensations; you must pick up these elements."

"When you open your five senses, recognize the entirety of your body's form, down to every single blood vessel within."

"This process will be extremely painful, but once you have remembered and absorbed many things, then eliminate the unnecessary parts. What remains are the essentials for that movement; seal them within."

"Over time, the blood vessels and muscles within your body will close off in this manner, and it will become as swift and simple as opening your eyes."

"Then, light will appear, the path will open, and your mind will naturally become transparent, allowing you to see the Transparent World."

"That is the domain that can only be reached after exerting all your strength, after a painful struggle."

These were the words Tanjiro's father had instructed him with before his death, the key to unlocking the Transparent World.

Uchiha Nagi was currently in front of a bonfire, performing the Kagura dance passed down in Tanjiro's family. As he danced, he closed his eyes, trying to sense that transparent world.

Compared to Tanjiro, Uchiha Nagi had a natural advantage. He had chosen to become a medical ninja and possessed a considerably strong understanding of the human body. It wasn't surprising that the domain of the Transparent World was connected to the Kagura dance.

This was because the creator of Sun Breathing was born naturally with the Transparent World domain, much like Hashirama's Sage Body. Therefore, Sun Breathing itself was a breathing method he created by observing the human body through the Transparent World.

First came the Transparent World, then came Sun Breathing.

Thus, by mastering Sun Breathing to its peak, one could reach the domain of the Transparent World. And hidden within the Kagura dance was Sun Breathing. By continuously comprehending and adjusting to the correct breathing during the dance, one could combine them to use Sun Breathing.

If the Kagura dance was performed incorrectly, one would only become increasingly tired. Conversely, if performed correctly, it would feel effortless and natural. This was how Tanjiro's father, despite his frail physique, could dance through an entire snowy night.

"Not quite right, something is a little off." Uchiha Nagi, after dancing for an hour, stopped and wiped the fine beads of sweat from his forehead.

"The Kagura dance movements are correct; my copy is flawless. But my breathing is wrong. Everyone's constitution is different, the heart's beating frequency is different, so the breathing method used will naturally be different. I should use a breathing frequency adapted to my own body, or one that suits my body's rhythm, to coordinate with this dance."

Uchiha Nagi pondered for a moment and created ten Shadow Clones. Although Shadow Clones would disperse if they used Breathing Style movements that were too large, they were excellent for accumulating experience. If they dispersed, he could just create a few more.

Through his research during this period, Uchiha Nagi had discovered that Breathing Styles were actually a type of technique that used breathing to amplify sword skills and the body.

Shadow Clones, being inherently transformations of chakra, would find it difficult to maintain their previous stability once they used Breathing Styles for amplification, which was why they dispersed upon using them.

However, even if a Shadow Clone could only use a Breathing Style once before dispersing, it was still a gain. Quantity could lead to a qualitative change, after all.

Moreover, during this time, Uchiha Nagi's body and chakra had begun a second phase of development. Normally, after the age of eighteen, chakra growth would slow considerably. But after awakening the Mangekyo Sharingan, it had begun to surge wildly. He knew that awakening the Uchiha Mangekyo would cause an unreasonable spike in chakra, but after receiving the White Zetsu arm cells, it grew even faster.

Especially after the battle with Akaza, Uchiha Nagi estimated that if his strength in Konoha was "one Kakashi," then it became "two Kakashis" later on. After fighting Akaza with all his might, it had now risen to at least "four Kakashis."

So, his current physical energy was roughly equivalent to nearly four Kakashis?

If he were to fight Akaza again, he could last much longer and have a greater advantage. He was improving every day, while Akaza's progress was slow.

"Caw~ Mission, caw~ Mission~~" Uchiha Nagi's personal Kasugai Crow circled in the sky before landing on his shoulder.

"Hmm?! A mission?" Uchiha Nagi was a little curious. It had been so long; this seemed to be only his second mission.

Well, it was fine. He'd go check it out. He had been training for so long; it was about time he went out and tested his results in actual combat.

With a few leaps, he arrived at another small mountain. This area was planted full of wisteria flowers. It was Ubuyashiki Kagaya's residence, though his place of dwelling wasn't actually fixed; he would change locations periodically. The reason was that Ubuyashiki Kagaya never allowed Demon Slayer Corps members to stay and protect him. According to him, if they could eliminate one more demon, ordinary people would be one degree safer, while he himself was a useless person. It wasn't worth having powerful Hashira stay to protect a useless person.

Those unaware of the Ubuyashiki clan's special abilities might be deeply moved by his words, but Uchiha Nagi knew that besides the curse passed down through their generations, their family also possessed a hereditary partial precognitive ability. Ubuyashiki Kagaya had once said that, relying on this precognitive ability, their clan had accumulated immense wealth, enabling them to sustain the vast expenses of the Demon Slayer Corps for so many years. Because of this partial precognition, Ubuyashiki Kagaya would relocate whenever he sensed danger.

"Ubuyashiki-san, were you looking for me?" Uchiha Nagi didn't address him as "Master"; he wouldn't be anyone's subordinate.

Ubuyashiki Kagaya didn't mind this. He opened his already blind eyes and smiled. "You've come, Nagi-kun. Please, sit. This is freshly picked wisteria flower tea."

Uchiha Nagi didn't stand on ceremony, poured himself a cup, and waited for the mission details.

"Sigh, recently, there's a place where people have been frequently disappearing. I sent swordsmen to investigate, but they all vanished. Later, Tomioka Giyuu-san went, but found nothing at all; the opponent seemed to have hidden."

"Then, as soon as Tomioka Giyuu-san left, people started disappearing there again."

At this point, Ubuyashiki Kagaya paused, his expression serious. "I suspect the opponent possesses a very powerful reconnaissance-type Blood Demon Art and detected Tomioka-san in advance. So, I'd like to ask you to make a trip, because only you possess those unique ninjutsu that other members don't have."

Uchiha Nagi nodded. "Alright, I'll prepare and set out immediately."

"Thank you for your trouble, Nagi-kun."

"It's what I should do."

"By the way, after this mission is over, I'd like to request some leave from you. I have some matters to attend to."

"Of course, you may."

Uchiha Nagi didn't waste words, immediately got up, and went back to prepare. During this time, he had taken a considerable amount of money from Ubuyashiki for various materials and equipment needed for his research. It was only natural to take people's money and help them avert disasters. Whether it was researching White Zetsu cells or demon cells, many things needed to be purchased: medicinal herbs, equipment, nutrient solutions, etc.

Recently, another item had been added to the list: Genya's demon-eating constitution. Uchiha Nagi was even wondering if he could analyze Genya's ability to eat demons and make immortality a reality without altering his own genes.