Natural Energy

So-called natural energy was a trace element present in the air, born of nature itself. Unlike chakra, it was energy that had spilled out during the growth of the Divine Tree, from the Divine Tree's fruit.

Kakashi, who knew the original story, understood more clearly than Orochimaru and the others that chakra was merely something foreign. The idea that chakra was extracted from physical energy and spiritual energy was simply a misunderstanding.

The correct explanation was that the people of this world had been eroded by chakra generation after generation since their ancestors' time. Over the years, everyone's body had come to bear traces of chakra, differing only in amount.

Through continuous physical training afterward, the chakra within the body resonated with the chakra in the surrounding air, drawing external chakra into the body. As the amount of chakra inside increased, it improved one's physical qualities on one hand while forcing the development of the brain's spiritual energy on the other. The excessive chakra energy within required stronger spiritual power to control and manage it.

Perhaps that was why every powerful ninja possessed their own unique beliefs and convictions, and pursued them unwaveringly.

In order to better manage and control the ever-growing chakra energy within their bodies, ninja passively developed and excavated their spiritual potential. Because such a spiritual outlook formed passively, it often lacked careful thought and guidance. More often, it became a one-sided perspective shaped by whatever emotion they desired most or resented most deeply at the time.

At that moment, the natural energy within Ryūchi Cave was so dense it was almost tangible, and it greatly stirred Kakashi's interest. Every cell in his body clamored restlessly, as if they wanted to devour it in great gulps.

Kakashi forcibly suppressed his body's instincts and looked expectantly at the beautiful but dangerous woman before him.

"Ah, Kakashi-kun really is impatient. But Senjutsu is not so easily mastered. Let me first explain the principles of natural energy, chakra, and Senjutsu." Tagorihime smiled faintly and tucked back a strand of hair. Her expression was slightly unnatural. She seemed to recall how vastly different her current attitude was from how she had treated past trial-takers. In the past, whenever she watched someone come to Ryūchi Cave to undergo Senjutsu training, she saw nothing but walking food. If they failed to withstand her genjutsu trial, she would simply devour them. Yet before Kakashi, she did not dare entertain any such thoughts. The White Snake Sage had seemed kind and benevolent just moments ago, but Tagorihime and the other two divine envoys had served her for ages and had seen the White Snake Sage's terrifying side many times. Within Ryūchi Cave, the White Snake Sage's words were fate itself. No living being dependent on her existence here dared disobey her in the slightest.

"Natural energy, as the name suggests, is energy naturally born between heaven and earth. It drifts through the air, unseen and imperceptible. Its concentration outside cannot compare with that of the sacred lands, because Ryūchi Cave was built around a spring where natural energy was born. But natural energy is violent and disorderly. Ordinary living beings will suffer adverse reactions if exposed to too much of it, which is why a great existence such as the White Snake Sage is needed to suppress it here..."

Tagorihime paused, seemingly realizing she had said too much, then changed the subject.

"You should be even more familiar with chakra than I am, so I will not say much else about it. The key difference between Ryūchi Cave's Senjutsu and the other two inheritances is that we use natural energy as the main component and chakra as a supplement, with your original physical energy serving as the balancing factor. The mixing ratio of the three is 1.5:0.5:1. Chakra is actually required in the smallest amount. However, the corresponding requirements for chakra quality are the highest among the three inheritances." Seemingly a little proud, Tagorihime carefully examined the chakra within Kakashi's body.

"To give a simple example, if Mount Myoboku's Senjutsu requires its user to possess at least the chakra reserves of a Jonin in order to match natural energy, then Ryūchi Cave's Senjutsu requires the user to possess chakra quality at least at the Jonin level as a catalyst for using Senjutsu. In the common terms of the Shinobi World, you must at least have chakra capable of shape transformation before you can use it." Looking at Kakashi, who was only five or six years old, Tagorihime truly could not understand why the White Snake Sage believed he could master Senjutsu. He had not even crossed the minimum threshold. It was impossible for someone his age to possess the ability to shape-transform chakra.

"And that is only the threshold. Once you have mastered shape-transforming chakra, you can step through the door, but the trials afterward are what truly matter. Ryūchi Cave's natural energy is incomparably violent. Once absorbed into the body, it produces hallucinatory effects. You need sufficiently powerful spiritual energy to control it, then follow the proper ratio to fuse the three energies within your body. What you ultimately unleash is Senjutsu."

After saying all that, Tagorihime looked at Kakashi curiously.

"Thank you, Elder Tagorihime, for clearing that up. I would like to try taking a small amount of natural energy into my body first, to see whether my body can adapt to it." Kakashi spoke calmly. "At present, my chakra control is indeed not sufficient to cause shape transformation, but I am not far from that point. If I can adapt to natural energy now, then once my chakra control improves further, mastering Senjutsu should come naturally." The youth's confidence once again startled Tagorihime.

"That kind of shortcut is not impossible. After all, I will be guarding you from the side, which is far more useful than having Orochimaru-kun help you. Perhaps he is stronger than I am, but when it comes to mastering Senjutsu, he is far inferior to me. If the natural energy in your body loses control or becomes excessive, I will immediately strip it out." With that, Tagorihime gestured for Kakashi to sit cross-legged.

After teaching him how to sense and absorb natural energy, Tagorihime's expression became somewhat more serious. From this point on, she needed to keep a constant eye on the boy beside her. The instant she noticed anything wrong, she would have to act immediately. If her negligence caused something irreparable, the White Snake Sage would skin and devour her alive.

With his eyes closed in concentration, Kakashi vaguely felt as though he stood amid a field of purple mist.

The mist surrounding him pressed close to his body, wrapping him in thick layers. Yet his body seemed to possess a thin membrane that blocked its invasion, preventing it from entering his flesh and tissues.

Kakashi, who had long suspected this, gathered his focus once more and contracted the chakra throughout his body. Like clearing the field behind fortified walls, he left not a trace of chakra in the surface tissues of his body, drawing it all into his internal organs and tissues.

In their daily lives, training, and battles, ninja unconsciously used chakra. Their limbs, organs, and everything else bore traces of chakra use, and after enough repetitions, some residue would inevitably remain. But this residual chakra was beneficial and harmless to ninja, so no one had ever investigated it closely. At this moment, however, it became an obstacle to Kakashi's absorption of natural energy.

My earlier judgment was correct. As time passes and the residual chakra within my body increases, directly absorbing natural energy into my body will become increasingly difficult, perhaps even impossible. Chakra and natural energy are originally two energy forms of equal quality. They can be made compatible through certain techniques, but the two cannot naturally coexist. So the oil Mount Myoboku applies to the body not only attracts natural energy into it, but also suppresses the chakra at the body's surface. No wonder failing to establish a stable energy ratio within the body immediately results in petrification. Without the suppression of Toad Oil inside the body, chakra and natural energy clash, causing it.

The purple mist of natural energy slowly seeped into Kakashi's body. Kakashi's naturally abundant spiritual power controlled his spiritual energy, guiding his chakra to evade it while also coaxing the natural energy to circulate slowly within him.

Why did Ryūchi Cave's natural energy cause hallucinations? Because Ryūchi Cave's natural energy truly loved charging toward the brain. Kakashi, who was straining to suppress the natural energy with spiritual energy, could not help feeling a little helpless.