Requirements for Cultivating Immortal Arts

Nagato had neither the time nor the inclination to visit Mount Myoboku or Ryūchi Cave.

Compared to the sages of those two places, Sage Katsuyu was by nature the most gentle. Having now received his warning in the form of 600 billion paper bombs, she likely wouldn't intentionally sabotage him or treat him differently. Nagato felt at ease with Katsuyu, convinced that Shikkotsu Forest was his best option.

He wouldn't even consider Mount Myoboku; it was part of the hostile faction. Ryūchi Cave was even worse than Mount Myoboku, as it belonged to the chaotic evil faction. The White Snake Sage taught senjutsu by injecting natural energy into practitioners using her fangs. How much she injected, or whether there were pathogens involved, was impossible for anyone to know. Most ridiculous of all, the White Snake Sage was always prepared to devour those who failed the training.

It was absurd; what sane person would trust a snake that intended to eat them?

Learning senjutsu in such a place and surrendering his fate to the White Snake Sage was not something Nagato would ever consider. Therefore, he couldn't accept her proposition.

"Are you that worried that Konan will blow up your pathetic forest?" Nagato asked through the Asura Path, his tone tinged with disdain. He felt Katsuyu was being small-minded—could she really be a homebody bug?

"Don't talk nonsense. It's not your home, how could you possibly understand?" the small Katsuyu chirped indignantly in her cute voice.

Looking at her now, she was truly soft, cute, and adorable. Yet, who would have thought that such a gentle creature would have such terrifying methods for teaching senjutsu back home?

"Actually, you could think of it this way: what if even if I died, Konan wouldn't blow up your forest?" Nagato asked tentatively.

"I am a practitioner of senjutsu! Senjutsu! Do you think I couldn't feel the determination of your companion to protect you?" Sage Katsuyu had already confirmed it; when Konan followed Nagato's orders and revealed the 600 billion paper bombs, she had been truly prepared to level Shikkotsu Forest. Otherwise, why would she have been so nervous?

"Oh, so you could tell? Then I'm relieved..." The Asura Path nodded. "I was afraid you were harboring wishful thinking."

Konan was absolutely a reliable companion, the kind to whom he could trust his back without hesitation. Nagato was certain of this.

"You..." Katsuyu felt a bit stifled. After all that, this was what he was trying to confirm?

"If you want me to give up, don't bother. I'll be blunt: my goal is to become a true god. If I can't even master the senjutsu here, then dying early is an acceptable outcome."

He had lived a life of mediocrity in his previous life; now that he finally had the chance to live again, how could he live it in fear? Nagato felt that, as a transmigrator, he had already died once, so dying again was no big deal.

Dying on the path to becoming the strongest was better than living a life of insignificance.

"You guy..."

Perhaps infected by the sheer force of will erupting from the depths of Nagato's soul at that moment, there was a hint of helplessness in Katsuyu's voice.

"However, even if I am to die, I must die with clarity," the Asura Path continued. "You said no one has ever mastered your senjutsu—is that because the Otsutsuki clan has never come here?"

"You even know about the Otsutsuki?" Katsuyu asked in surprise, seemingly shocked by Nagato's knowledge. "But the reality isn't what you think. Fine, since you have such courage, I'll tell you. When people speak of the Otsutsuki clan, they are mostly referring to the lineage of Otsutsuki Hagoromo. The descendants of Hagoromo are divided by talent into the Sage Eye and the Sage Body. Inheritors of the Sage Eye lack the massive chakra reserves required to practice senjutsu. As for inheritors of the Sage Body, they don't meet the chakra requirements until they approach a mature state. Once they reach maturity, the Sage Body automatically senses natural energy and masters senjutsu; there is no need to go elsewhere to learn it."

Nagato pondered for a moment before having the Asura Path continue: "So, any mature Sage Body can master the senjutsu of Shikkotsu Forest?"

"No," Katsuyu denied it flatly. "A mature Sage Body automatically senses, absorbs, and utilizes natural energy. The energy within the Black Water can no longer affect them, so they cannot learn the senjutsu of Shikkotsu Forest."

"What do you mean?"

"You don't need to know that much. Forget it, you can understand it this way: the senjutsu of every holy land is equivalent to a unique form of chakra specific to that place. Learning the senjutsu of a holy land is equivalent to the process of being influenced by that unique chakra. A mature Sage Body already possesses its own senjutsu chakra and is unaffected by the holy land's senjutsu. Take the acid in the Black Pool of Shikkotsu Forest; it is a type of acid unique to my body that can be neutralized by natural energy. Once a mature Sage Body enters the Black Pool, they are unaffected by it."

Nagato immediately thought of the time he had controlled the Preta Path and witnessed its resistance to Naruto's natural energy, but he still had the Asura Path argue: "What about the situation at Mount Myoboku? Didn't Naruto learn it? And Ryūchi Cave, too."

Katsuyu was silent for a moment, then suddenly asked: "Do you really intend to learn the senjutsu of Shikkotsu Forest?"

Nagato felt like scratching his head. Why is this big bug asking this again? He could only reply through the Asura Path: "Yes!"

"Even knowing you will die, you still want to learn?"

Nagato frowned, thinking the bug was insane.

"Yes!"

Katsuyu was silent for another moment: "Fine, you're going to die anyway! I'll tell you: the methods used by Mount Myoboku and Ryūchi Cave are nothing more than half-baked amateurism."

"What do you mean?" the Asura Path asked immediately.

"It means that such methods can never reach the advanced stages of senjutsu, and even intermediate levels are difficult to attain."

"Senjutsu has levels?!"

"Heh." Katsuyu scoffed and fell silent.

Nagato couldn't help but rub his forehead, feeling a bit dizzy. As a transmigrator, his greatest pride had been his mastery of the world's secrets, but it seemed there were too many unsolved mysteries in the world of Naruto.

"It seems you don't intend to tell me the levels of senjutsu?" The Asura Path's voice was helpless. "Then you must at least tell me the requirements for practicing the senjutsu of Shikkotsu Forest."

After Tsunade learned of the difficulty of practicing senjutsu in Shikkotsu Forest, she had chosen to give up, given her expertise in acids. Therefore, even Tsunade didn't know the specific requirements, and Nagato couldn't learn them from her.

Katsuyu's four tentacles twitched: "Of course I will tell you. After all, it seems you have made up your mind to be the successor of my senjutsu; you can consider yourself my child."

Nagato's mouth twitched. He really didn't know how this bug's brain worked.

Katsuyu said earnestly: "Speaking of which, on the surface, you actually seem quite suited for my senjutsu. It's a pity that in reality, you fail in every category. I estimate that if you actually entered the Black Pool, you wouldn't last a few seconds before there was nothing left of your bones. First, humans who wish to learn the senjutsu of Shikkotsu Forest require massive chakra reserves approaching that of a Sage Body. Second, they need strong—but not excessively strong—chakra control, and the ability to resist the Wraiths."

Nagato couldn't help but straighten his back, having the Asura Path speak: "You might not believe it, but I actually have a Sage Body."

Katsuyu: ...

Nagato seemed to hear the sound of Katsuyu mocking him.

"Well, that's a very funny joke. I will try to remember it for a long time after you die," Katsuyu said in a voice suppressing laughter.

"What do you mean? I really am a Sage Body."

"With that... amount of chakra?" The amusement in Katsuyu's voice was almost impossible to suppress.

"That... amount?" Nagato was shocked. His chakra reserves were astounding, weren't they? He had leveled all of Konoha without feeling drained. However, he suddenly recalled the chakra reserves of Hashirama Senju, another Sage Body. Emmm, alright, there seems to be a bit of a gap there.