Chapter 17: A Theory on Senjutsu Chakra and a Treatment Plan
After leaping down from the Slug Sage's head and landing back on the giant mushroom, Shen looked up to find the enormous Slug Sage gazing at him with obvious curiosity. He felt a small swell of pride. Ninjutsu and hand seals had originally been created by Indra, the son of the Sage of Six Paths—an invention so brilliant that even the Sage of Six Paths had highly praised it. But at this point in history, they had not yet appeared. Relying on the memories of his previous life, Shen had brought them into existence ahead of time, and unexpectedly, he had even earned the Slug Sage's admiration.
"These are hand seals. They're a method I invented to make chakra easier to control and use. By combining different hand seals and supplementing them with precise chakra control, one can activate ninjutsu. For example—Fire Release: Great Fireball Technique!"
Shen's fingers flashed through a string of seals, and in the next instant, a massive fireball burst from his mouth.
"This… this is truly incredible! To be honest, an energy like chakra is simply far too miraculous!" the Slug Sage exclaimed as she watched Shen unleash the Great Fireball.
"Hm? Isn't Senjutsu the same?" Shen asked curiously. In his memory, Senjutsu was an extremely powerful force, so the energy it relied upon could not possibly be ordinary.
"The use of Senjutsu depends on natural energy, and natural energy is the power of the world itself. The world's power does not possess such attribute transformations. In truth, Senjutsu's function is to strengthen the body, and when we attack, the power of those attacks can be amplified to varying degrees depending on the results of our Senjutsu cultivation. In the end, it merely enhances our innate talents."
"For example, me—my innate talent is healing, so I am almost never injured, and my lifespan is extraordinarily long. My only offensive method is acid. You've seen ordinary slugs in this world before. Even if they can spit acid, they are nowhere near as powerful as I am. That is only because my attacks have been enhanced by Senjutsu energy."
"Of course, because of our long lifespans and our unique inheritances of Sage Arts, we can also use certain special techniques, such as the toad clan's sage talismans, the white snake clan's inorganic reincarnation, and my own splitting and healing. But even so, Senjutsu is nowhere near as versatile as chakra." The Slug Sage shook her head as she explained the effects of Senjutsu energy.
"So that's how it is." Shen nodded in understanding. It seemed that aside from the inherited Sage Arts of the Three Great Sage Lands, the primary uses of Senjutsu were strengthening the body and enhancing innate attacks.
"Then… would you like to try cultivating chakra?"
"Hm? You're willing to teach me? Wasn't this something you created for humans?" the Slug Sage asked in surprise once again. In her eyes, the method of cultivating chakra had been devised by Shen specifically for humanity. She had not expected to be given the chance to learn it herself.
"Chakra cultivation has nothing to do with species. Chakra is simply a form of power extracted from physical energy and spiritual energy. Since you've cultivated Senjutsu energy for countless years, you should be able to learn it very quickly."
"But ordinary chakra doesn't really suit someone like you. Actually, I have an idea—that is, to combine physical energy, spiritual energy, and Senjutsu energy in a one-to-one-to-one ratio, then refine chakra from that mixture."
"If it works, I want to call this kind of chakra Senjutsu Chakra. Compared to ordinary chakra, Senjutsu Chakra should be far more powerful. And if you succeed, please summarize the cultivation method and pass it on to the other two Sage Lands. Also, if possible, I'd like to try cultivating Senjutsu Chakra as well!" Shen had formed this idea the moment the Slug Sage began explaining Senjutsu.
At this point in time, Senjutsu Chakra did not yet exist. There was only Senjutsu energy, cultivated from natural energy by the Three Great Sage Lands. As for Senjutsu Chakra, it would likely only be created more than ten years later by Ōtsutsuki Hagoromo.
He clearly remembered that Hagoromo and his younger brother had learned Senjutsu from the toad clan of Mount Myōboku in order to oppose Kaguya. It was probably during that process that Senjutsu Chakra had first come into being. Later, the toads of Mount Myōboku successfully systematized the cultivation method, and from there, the Three Great Sage Lands each developed their own unique Sage Arts based on that foundation.
"Oh? That is quite an innovative idea. I can give it a try." After thinking it over for a moment, the Slug Sage agreed to Shen's proposal. She was genuinely interested in mastering a power as flexible and adaptable as chakra.
After that, Shen taught the Slug Sage how to cultivate chakra, including the advanced chakra refinement method he himself used. Since the Slug Sage already cultivated natural energy by nature, she had no need to fear the risk of being assimilated by it.
Watching the Slug Sage fall silent in thought before him, Shen knew she was attempting to cultivate chakra. Before long, he sharply sensed chakra appearing within her body. Activating his Byakugan, he indeed saw green chakra circulating inside the Slug Sage.
"As expected of the Slug Sage. Even compared to the Ōtsutsuki Clan, you lose nothing. Our clan is born with an extraordinary sensitivity to chakra, yet even our cultivation speed is only about this fast," Shen said with a sigh of admiration.
"It's not as impressive as you make it sound. I'm merely relying on the accumulation of time. My body has always been strong, and spiritual power depends on the heart and one's experiences. I've lived for so long that I no longer even know my own age. Being able to refine chakra so easily is simply a gift granted by time." The Slug Sage answered with gentle humility.
Shen smiled as he looked at the mild and graceful Slug Sage. That was precisely why he liked her so much. She did not seek dominance, treated others with quiet kindness, remained humble and courteous, and viewed everyone as equals. Compared to the Great Sages of the other two Sage Lands, Shen felt that the Slug Sage was the one who truly deserved the title of sage.
"Then I'll leave the development of Senjutsu Chakra to you!" Shen bowed deeply to the Slug Sage. This was the key to whether he could begin cultivating Sage Arts ahead of time. Just thinking about all those Rasengan from his previous life—Big Ball Rasengan, Massive Rasengan, Rasenshuriken—was enough to set his blood boiling.
And unlike Naruto, who had only a single attribute, he himself possessed all attributes. He could make whatever kind of "ball" he wanted. If he hurled enough of them at an enemy, there wouldn't be anything left of the target.
"Mm, leave it to me. As soon as the method for cultivating Senjutsu Chakra is complete, I'll summon you," the Slug Sage said with a nod, giving her promise.
"Next comes your own matter—treating your injuries. Let me take you to my main body. That will be safer, and the chances of success will be higher. Although I am overall the Slug Sage, I am still only a split body."
"Alright, then I'll trouble you." Shen bowed to the Slug Sage, then jumped from the giant mushroom onto her head. The Slug Sage turned and began moving toward her true body.
As the Slug Sage moved, the mushrooms around them seemed to slide backward one after another. Yes, it was the mushrooms that seemed to be moving, because Shen could not feel even the slightest vibration that would indicate the Slug Sage herself was in motion. It felt as though the scenery itself was retreating of its own accord.
The Slug Sage was not slow at all. Though she was not as fast as the inhabitants of the other two Sage Lands, compared to humans her speed was astonishingly high. Even some ordinary jōnin would not be able to move that quickly. Shen judged that unless he took to the air, he would never be able to keep pace with her.
The Slug Sage moved while eating. Whenever a giant mushroom in front of her came within reach, it would steadily shrink lower and lower until it disappeared entirely. But when Shen turned around and looked behind them, he saw that along the path she had passed, one mushroom after another was already sprouting again. Though smaller than before, they were visibly growing at a rapid pace.
Sensing Shen's confusion, the Slug Sage explained, "Because my body is so large, I need to eat constantly. But every time I feed, I leave behind a trace of my own unique Senjutsu energy. Because of that, these mushrooms grow rapidly under the combined influence of my Senjutsu energy and the dense natural energy here. In turn, I gain an inexhaustible source of food."
Shen nodded in sudden understanding. Wasn't this basically the very definition of sustainable development and recycling from his previous life? As expected of the Slug Sage—even the way she handled things was this advanced.
After traveling for around ten minutes, Shen finally saw an incomparably gigantic figure in the distance. It was so vast and towering that it almost resembled a mountain. His mouth fell open as he stared at that colossal shape ahead of him in astonishment.
"So… huge!"
Before long, Shen arrived beside the Slug Sage's true body. With understanding, he jumped onto the top of a giant mushroom and watched as the split body merged back into the Slug Sage's main body.
"Shen-kun, please place your hand on my tentacle." It was still that same gentle voice. Even though her size had increased beyond imagination, her voice had not changed in the slightest.
Looking at the pale tentacle extended before him, Shen reached out and pressed his hand against it. Instantly, he felt a surge of energy overflowing with life force enter his body. No—it would be more accurate to say that what entered him was vitality compressed to an almost inconceivable degree. Feeling that boundless life force, Shen could not help but marvel. No wonder the Slug Sage had been able to live for so long.
The Slug Sage slowly withdrew her tentacle and said, "Shen-kun, I now understand the condition of your body. I can treat you, but you will need to be absorbed into my body, and the treatment will require half a year. Is that acceptable?"
"Half a year?" Shen frowned unconsciously. He still needed to guide the Yokota Clan in their cultivation and lead them into seclusion within the Southern Frontier Great Forest. And in order to prevent Kaguya from possibly noticing the chakra activity here, he would also need to establish a barrier capable of blocking the Divine Tree's perception.
Now Shen faced a choice: remain here for half a year and complete the treatment first, then use his increased strength to quickly establish the barrier and hide everyone away—or leave first, slowly construct the barrier to protect the Yokota Clan, and only return for treatment after the barrier was complete.
"What is it, Shen-kun?" the Slug Sage asked when she saw him struggling with the decision. Shen explained his concerns, and for a moment, even the Slug Sage had no ideal solution. The Yokota Clan was simply too weak at present. Without Shen's help, they had no hope of resisting Kaguya. But if Shen wanted the strength to stand against Kaguya, healing his injuries was absolutely necessary.
In half a year, Kaguya would long since have given birth and recovered. And with the Divine Tree continuously supplying her with chakra, the current Shen had no chance of resisting her. Even if he summoned the Slug Sage now, what he could bring forth would only be a split body, and not a particularly strong one at that. After all, his chakra reserves were still only at the level of a chūnin.
"Mm… how about this? I can separate a split body and have it remain attached to you at all times. Through the connection between us, it can continuously provide you with enough life force. That way, even if you over-refine chakra, your injuries will not worsen."
"In that case, you can increase your strength and speed up the creation of the barrier. Then, once the barrier is complete, you can return to me for the half-year treatment. What do you think, Shen-kun?" After considering the matter for a while, the Slug Sage offered her suggestion.
"That's possible?!" Shen asked in delight. If that was truly possible, then this plan really could work. Although the chakra he cultivated would not be able to remain for very long, that would not matter if he only used it to establish the barrier. This truly was the best of both worlds.
The Slug Sage looked at Shen and nodded. Then she directly split off a clone. It was not large, only about the size of a fist. After climbing onto Shen's shoulder, the slug clone said to him, "I'll be in your care from now on."
"No, that's what I should be saying. Please take care of me, Slug Sage!" Shen replied as he looked at the slug on his shoulder. He knew that every split body of the Slug Sage possessed an independent mind, so he treated this clone with the same respect.