"You've already helped me a lot by stitching the blood vessels and muscles in my arm back together." Uchiha Nagi was soaked to the bone, as if she had just come out of the water.
No matter how many shadow clones there are, each only has one hand, so it's not as convenient as having two hands to coordinate. Moreover, Tamayo's technique is very skillful.
Uchiha Nagi stretched out her fingers. Although she had just undergone surgery, she was already able to control her fingers, which was truly amazing, a testament to the incredible power of White Zetsu cells.
He could even feel an intense itch in his bones, muscles, blood vessels, and nerves. This was a sign of rapid cell regeneration, with his blood constantly circulating through Bai Jue's arms.
The White Zetsu's arm absorbed nutrients and chakra from the blood, and the cells began to grow wildly to heal the severed arm. It is believed that the bone at the severed arm will heal in less than a day, and the arm will be able to be used normally in three or four days.
More importantly, there seemed to be an inexplicable substance within the White Zetsu cells, slowly circulating through his bloodstream. His Mangekyou Sharingan, which he had previously used, seemed less fatigued. A cool sensation began to flow into his eyes, and even his severely damaged left eye was slowly recovering. He believed he could use it again in less than a year.
"I have received a reply. Mr. Kagaya Ubuyashiki welcomes you to his new position and invites you to the Demon Slayer Corps headquarters. Please rest for a few days and set off with Tanjiro once you have recovered from your injuries."
"Yes, thank you very much."
"If you take someone's money, you have to do their bidding." Uchiha Nagi wanted to learn the breathing techniques of this world, so joining the Demon Slayer Corps to help was perfectly reasonable. Moreover, compared to the ninja world where one is constantly being defeated by a small team of ninjas with different abilities, there are far fewer demons in this world.
Most of the time, it's the Demon Slayer Corps that outnumbers the demons and turns the tables on them. And as long as they're under the sun, they can completely relax and don't have to worry about being ambushed.
In the world of ninjas, you have to worry about being poisoned or ambushed when you eat, sleep, or even play cards with a woman. Especially in Konoha, even Uchiha Nagi can't be at ease because there's a ruthless ninja who wants to gouge out Sharingan from time to time.
Then, as promised, Uchiha Nagi began exchanging medical knowledge with Tamayo, explaining the principles of the Healing Palm Technique. "Chakra? Is this the basic energy required for your amazing techniques? That's truly amazing. This is the first time I've ever heard of humans having something called chakra besides breathing techniques."
Tamayo sighed, "According to what you said, extracting cells from the human body is similar to our Blood Demon Art. However, once we start converting a human body into a demon, we may not be able to extract the kind of energy you mentioned. We can only use Blood Demon Art."
Uchiha Nagi said, "Blood Demon Art seems to be a technique that comes from your genes combined with your own. Each demon cannot copy the Blood Demon Art of other demons, right? But chakra can be used to cast all techniques that are universal to humans. However, the specifics still need to be verified slowly."
Because no one in this world has chakra, and it's unknown whether it's possible to learn it, it remains to be studied.
As for breathing techniques, Nagi Uchiha was certain that she could use them, and she could easily copy Tanjiro's Water Breathing.
Aside from having a relatively weak earth attribute, fire is the strongest, while water, lightning, and wind are of medium strength, so copying Tanjiro's Water Breathing technique is not difficult for me.
Furthermore, if chakra nature can be enhanced through development, then why can't breathing techniques of different natures be developed as well?
Kakashi continuously developed his different attributes, eventually becoming the Copy Ninja. He was born with a weaker attribute, but he could enhance it through development.
Getting back to the point, after chatting with Tamayo for a while, Uchiha Nagi came to the ground. During the day, Tamayo and the others couldn't come out, but Tanjiro could.
Tanjiro was practicing his breathing techniques in the dilapidated courtyard, then combining them with his swordsmanship to unleash cool moves.
After watching for a while, Uchiha Nagi called out to Tanjiro, "Tanjiro, I have something I want to discuss with you."
Tanjiro turned around, sheathed his sword, and walked over. "Mr. Uchiha, is your surgery finished?"
"Incredible! You actually have this ability? You can even reattach a severed hand?" Tanjiro exclaimed in amazement as he looked at Uchiha Nagi's severed hand.
"Hehe, if you want to learn, I can teach you. By the way, may I see your Water Breathing Technique? In exchange, I can teach you some other things."
After saying that, Uchiha Nagi formed a hand seal with one hand and released a shadow clone. Then, the two clones worked together to form a series of hand seals. After a series of dazzling hand seals, a water release technique appeared in front of Tanjiro.
"Water Release: Water Dragon Technique~"
A colossal dragon made of water soared into the sky, then crashed into and knocked down a large number of trees in the forest. This massive spectacle was simply—awesome.
"Hiss—Skui~" Tanjiro breathed heavily. "That's amazing, Mr. Uchiha. Your breathing technique is incredible, and you can even create clones. Would you really like to teach me? Oh no, I mean, you can learn my Water Breathing technique as you like, and it's okay if you don't teach me yours~" Uchiha Nagi smiled. "I'm only a few years older than you. Just call me Nagi-nii. There's no need to call me 'Mr.' or it makes me sound old."
"What I know is called ninjutsu, not breathing techniques. It requires refining a type of chakra from the human body to use as energy. This clone is called Shadow Clone Technique, which is a physical clone. However, I can't guarantee whether you can learn it unless you can successfully refine your chakra."
Tanjiro stared at Nagi's shadow clones with burning desire. Who wouldn't want to learn such an amazing ninjutsu? If he could create a dozen or so clones, each wielding a Nichirin Blade, every time he fought a demon...
"Slurp~" Just thinking about it made Tanjiro's mouth water.
Moreover, that ninjutsu that allows him to control water looks amazing. Despite the name "Water Breathing," there isn't actually a bunch of water surrounding his body during battle; it's just a breathing technique combined with sword skills.
"Chakra is a type of energy produced by the perfect fusion of various components of energy in the human body. It is the energy source for performing ninjutsu, genjutsu, and taijutsu."
"This energy is the energy drawn from each of the 130 trillion cells in the human body, one by one. It is also the spiritual energy cultivated through much practice and experience."
Uchiha Nagi added one last sentence in her mind: If one cultivates Sage Mode, then one part of it will be natural energy.
Sage Mode had always been something he longed for, but unfortunately, there was no one to guide him through the basics, and it was too difficult to learn it on his own. Even geniuses like Madara and the Second Hokage couldn't master Sage Mode.
They were both close siblings of the first generation, so the first generation would definitely not keep it to themselves. The fact that they couldn't learn it just shows that the threshold for immortal techniques is indeed too high.
As for Naruto and Jiraiya later on, their Sage Mode was only half-baked...