Rebirth

Nagato did not know how much time had passed, but once the Senjutsu Chakra meridians within his body were fully woven, he joyfully discovered that he no longer needed the healing techniques of Katsuyu. The new chakra meridians were radiating an increasingly powerful life force, warming his entire body and inevitably lifting his spirits.

The ratio of natural energy to the acidic fluid of Katsuyu within his muscles had gradually reached perfection. He could absorb and control more and more natural energy, giving him the sensation that he had merged with the Black Pool through the medium of natural energy.

This green natural energy acted like a catalyst, causing the new muscles in his body to sprout and grow with the vigor of bamboo shoots after a spring rain. It pushed the rotten flesh, which had previously resembled sludge, out from within his body, causing his entire frame to itch as if countless insects were crawling over him.

"Splash." A series of sounds echoed as the rotten flesh fell into the water. Nagato opened his intensely itching eyes and, by the moonlight, was pleasantly surprised to find his condition as good as if he had been reborn.

Although he had learned from Katsuyu that the Senjutsu here possessed healing properties, he had not expected it to reach such a degree.

At this moment, every cell in his body was brimming with vitality, and his skin had regrown, as fair as a newborn's and covered in green stripes. The lines were graceful and appeared extremely mysterious.

The Black Receivers on his body had long since vanished, and his once numb and heavy legs had become light and agile.

Comparing his current state to the Hashirama Senju from the memories of his two lives, Nagato felt that while his Sage Body still lagged behind Hashirama in terms of recovery speed and chakra volume, it seemed to surpass him in sheer life force and vitality. It gave Nagato the illusion that he was a cockroach, impossible to kill no matter what.

He felt that he was already the strongest living person in the world. Even without using the Six Paths of Pain, he had no fear of challenges from Obito or Black Zetsu.

The only ones who could be his enemies, he reckoned, were the dead. Thinking of this, Nagato lowered his head to gaze at the moonlight before him and sighed, "Oh, moonlight..."

Then, his eyeballs suddenly fell out.

His sigh, just barely uttered, turned into a cry of alarm: "Damn it! My eyes!"

He did not see that, at this moment, his two eye sockets were sprouting dense, granular flesh that was constantly writhing and intertwining, looking quite terrifying.

"It's not like they're your eyes, why are you in such a rush?" Katsuyu, perched on his shoulder, said speechlessly. "You truly are a Sage Body; in such a short time, you haven't just reshaped your chakra meridians, you've even regrown your eyes."

Katsuyu had calmed down by now, accepting the fact that Nagato had mastered Senjutsu.

Using the sensory perception of Sage Mode, Nagato fished the Rinnegan out of the Black Water. Finding them unharmed, he breathed a sigh of relief and asked, "Why weren't the Rinnegan corroded by the acid in the Black Water?"

"Because there is natural energy in the Black Water," Katsuyu replied. "If you want the Rinnegan to be corroded, I can spray acid specifically for you..."

"Heh," Nagato sneered. He pressed his fingers against his eye sockets to suppress the cellular vitality within them before reinstalling the Rinnegan. "That won't be necessary. Without these eyes, how else would I perform Shinra Tensei?"

Katsuyu shook its head. Although it did not know what "Shinra Tensei" meant, it could guess that it referred to the power of the Rinnegan. "Why cling to power that does not belong to you? I advise you to throw the Rinnegan away."

Perhaps because he had successfully cultivated Senjutsu, Nagato felt that Katsuyu's attitude toward him was much friendlier than before, no longer trying to chase him away at every turn.

However, he could not possibly give up the Rinnegan. Regardless of where the Rinnegan came from or who it originally belonged to, as long as it was in his hands, it was his—it had been his since ancient times!

"Are there any risks to the Senjutsu of Shikkotsu Forest?" Looking at the "forgiveness-colored" tattoos on his body, Nagato chose to change the subject. Just as there were things Katsuyu would not tell him, there were things he would not tell Katsuyu.

"Risks? How could there be risks in Senjutsu?" Katsuyu said, sounding slightly displeased.

Nagato blinked upon hearing this: "That's not right. As far as I know, the Senjutsu of Mount Myoboku carries risks. The same goes for Ryūchi Cave. Is the Senjutsu of Shikkotsu Forest truly so different?"

Katsuyu lowered its head to examine the calm surface of the Black Water: "Didn't I tell you? Those are just the half-baked practices of the younger generation."

Seeing Nagato continue to stare at it with a questioning gaze, Katsuyu sighed: "Fine. To answer this question, we must first clarify what Senjutsu is. You should understand by now, right? Senjutsu is merely the product of natural energy mixed with chakra, and natural energy is simply the energy that fills the sky, the earth, and all of nature. Think about it yourself: what risks could such energy possibly have?"

"But..." Nagato narrowed his eyes.

"I know what you want to say," Katsuyu interrupted. "You only need to know that natural energy is the energy of nature, representing wild life force. For all things in the world, natural energy is just like the chakra of you ninjas. If there were risks in this, life would not exist in this world."

After a moment of thought, Katsuyu added: "If you must speak of risks regarding natural energy, it would be the wildness within it. Ordinary creatures can only accept the influence of natural energy, but cannot master it. Furthermore, for you humans, if you absorb natural energy without restraint, you might temporarily lose your reason like a wild beast. But that is only the result of human greed; animals do not behave this way. As for you, now that you have learned to balance Senjutsu Chakra, as long as you don't act recklessly, there will be no risks."

Nagato frowned. He felt that what Katsuyu said made sense, yet it was completely different from the intelligence he had in his mind regarding Senjutsu.

With no time to dwell on it, he could only treat this as a unique benefit of the Shikkotsu Forest Senjutsu. In any case, it did him no harm.

"The power of this world, every drink and every peck, is destined by heaven," Katsuyu gazed at the black pool water, warning him with profound meaning. "I have lived in natural energy for so long to understand such a principle. Chasing power that one cannot master always comes with a price. Just like Senjutsu Chakra, the reason you were able to obtain the power of Senjutsu is not because of anything else, but because you possess a Sage Body. Even if you did nothing, as long as you were willing to discard the Rinnegan and heal your body, in a few years, once your Sage Body matured, you would have been able to enter Sage Mode all the same. But the Rinnegan is different; that is not power that belongs to you. The Rinnegan is the risk you should be considering."

Katsuyu's words seemed to point to something, hinting at a deeper meaning, but Nagato could not possibly take it to heart.

He certainly knew his Rinnegan was trouble, but so what? How could he give up power that was already in his hands? Nagato felt a bit helpless now, wondering what this feeling of being lectured by an elder was all about. Was Katsuyu his long-lost father? Bah, he wasn't some father-obsessed maniac, and besides, this creature used a female voice.

Tilting his head slightly, he saw that Katsuyu was still waiting for his response after finishing. Nagato looked left and right, searching for a new topic. Then, seeing the silvery moonlight on the Black Pool, his eyes lit up. Remembering his earlier exclamation, he asked Katsuyu: "What is the deal with this moonlight? Why can it penetrate the thick fog here? During the day, even the sunlight can't penetrate directly to this place, right?"