"Naruto, from now on, I will guide your training of Sage Mode." Fukasaku jumped in front of Naruto and looked up at him.
"The most important step in the training of Sage Mode is absorbing natural energy. Jiraiya should have told you that Sage Mode is based on physical energy and spiritual energy, absorbing the omnipresent natural energy from the natural world, and fusing the three in precise proportions to form Senjutsu Chakra."
"However, this fusion process is extremely dangerous, and a slight carelessness will lead to—"
Naruto took over the words, "Turning into a stone statue. Pervy Sage told me."
"Since you already know the theoretical basis, let's start directly." Fukasaku nodded.
Shima suddenly clapped her hands. "It's rare for Jiraiya and Naruto to come together. I'll make tonight's dinner, I'll make a big pot of delicious food for you two."
Jiraiya was still savoring the Great Toad Sage's prophecy from earlier. Hearing Shima's words, his entire body suddenly shuddered. The bug feast he enjoyed last time flashed through his mind.
He quickly took two steps back and squeezed out a brilliant smile toward Shima. "Um... Sage Shima, I suddenly remembered that if I don't submit the new volume manuscript of Icha Icha Paradise to my editor soon, they're going to storm Mount Myōboku. I need to hurry up and write the manuscript, so you don't need to wait for me for dinner."
Before his voice had even faded, his whole body turned into a puff of smoke and disappeared on the spot, moving so fast it was as if he were being chased by Naruto's Light Speed Kick.
Shima looked at the spot where Jiraiya had disappeared and snorted irritably. Then she turned to jump toward the direction of the kitchen.
"Old man, I'll call you when lunch is ready."
Fukasaku led Naruto across the training area of Mount Myōboku.
Along the way, they saw a massive dark red toad smoking a pipe by the pond.
Gamabunta spat out a smoke ring and lazily raised a paw toward Fukasaku. "Fukasaku-sama, how do you have time to come over here today..."
Halfway through his sentence, Gamabunta's gaze swept over Naruto behind Fukasaku, and his pipe almost slipped from the corner of his mouth.
He recognized who this black-haired boy was. Later, he learned from Jiraiya that this kid had beaten the fully Tailed Beast Transformed Eight-Tails Jinchuriki into submission.
"Gamabunta, long time no see." Naruto waved at Gamabunta.
"Yo... Naruto, came to Mount Myōboku to training?" Gamabunta responde.
Naruto nodded and continued walking toward the training grounds with Fukasaku.
Soon, Fukasaku brought Naruto to the depths of a valley.
The terrain here was completely different from the picturesque scenery of other parts of Mount Myōboku.
Right in the center of the valley was a fountain constantly gushing dark yellow viscous liquid, making gurgling bubbling sounds as the liquid flowed over the rocks.
Surrounding the oil spring were dozens of toad stone statues of various sizes. All of them were practitioners who had been thoroughly backlashed by natural energy after failing the training of Sage Mode.
"These are the stone statues Jiraiya told you about. Every single stone statue used to be a living Senjutsu aspirant."
"Once you start absorbing natural energy, you cannot move. If you move, the energy will go out of control. Therefore, it must be done under my supervision by your side. You must never secretly try it alone."
Fukasaku stopped in front of a small toad stone statue and solemnly glanced at Naruto.
Then he found a flat stone platform by the oil spring and motioned for Naruto to sit down.
"The first step of Sage Mode is perceiving natural energy. Only in a state of absolute stillness can the human body resonate with the energy in the natural world. Remember, absolutely do not move."
Naruto sat down and closed his eyes, his breathing gradually slowing down.
"The oil in this oil spring can accelerate the human body's contact with natural energy. I'll help you apply a little."
Fukasaku stretched out a front paw, dipped it into the oil spring to get some dark yellow oil, and evenly applied it to the back of Naruto's right hand.
In an instant, Naruto clearly sensed an overbearing and unfamiliar energy penetrating his skin through the oil layer, spreading upward along his arms along the Chakra pathways.
This energy was completely different from any Chakra he had contacted before. It was wild and difficult to control.
He lowered his head to look and saw that the skin on the back of his right hand was beginning to show subtle changes.
The color was shifting from normal skin tone to dark gray, with rough particles resembling toad skin surfacing on the skin.
Meanwhile, his entire right arm uncontrollably expanded and enlarged by a circle, looking as if it was about to undergo toadification.
Fukasaku was well prepared. He pulled out a black ruler specifically used to interrupt the erosion of natural energy and was about to bring it down on Naruto.
Before the ruler could fall, his movement stopped mid-air. He widened his eyes, staring intently at Naruto's right hand, only to find that the toadification, which had been visible to the naked eye just a moment ago, was now visibly receding.
The dark gray skin quickly faded upward from the back of the hand, and the rough toad particles smoothly sank beneath the normal skin tone. The entire right hand returned to normal within a few seconds.
Fukasaku's ruler hung in mid-air for a long time without falling.
Having lived for so many years and taught countless disciples Sage Mode, he had only ever used the ruler to beat a disciple's hand back to its original form from toadification, and had never seen any disciple reverse the toadification of their hand on their own.
"Naruto, how did you do that just now?"
"Controlling Chakra is my strong suit, Sage Fukasaku. After that strand of natural energy entered my body, I tried absorbing it myself, and it went quite smoothly." Naruto smiled.
Hearing this, Fukasaku silently put away the ruler.
Naruto sat by the oil spring and sank his consciousness into his body. Under Absolute Control, this strand of natural energy flowed slowly along his Chakra pathways like a murky river.
Completely different from Chakra, this energy was more primitive and wild, carrying a domineering aura that did not belong to humans.
Yet in front of Absolute Control, it was as docile as a newborn lamb. With a thought from Naruto, it was precisely fused with his physical energy and spiritual energy according to the proper ratio.
The three strands of energy converged and finally transformed into a strand of Senjutsu Chakra. However, the amount was far from enough.
To activate the complete Sage Mode, it was necessary to absorb more natural energy and accumulate enough Senjutsu Chakra within the body.
Moreover, true Sage Mode should not rely on external objects. Not using oil, but relying solely on oneself to perceive and absorb natural energy in a stationary state was the mark of a qualified Sage Mode.
Fortunately, the natural energy of Mount Myōboku was extremely rich.
Naruto stood up from the stone platform and looked at the continuously gushing fountain.
Just as Fukasaku was putting away the ruler, he saw Naruto stand up, thinking that Naruto was going to change locations to continue meditating.
He didn't expect Naruto to stop by the fountain, turn around, and say to him, "Sage Fukasaku, I'll have to trouble you next."
"Naruto, what trouble is there to speak of? Teaching Sage Mode is inherently my..."
Before Fukasaku finished speaking, he saw Naruto leap forward, diving with a splash straight into the fountain pool. The yellow oil splashed up a large amount of liquid, and the ruler in his hand dropped straight to the ground.
"Naruto, no! That is the crude oil with the highest concentration! Hurry up and come back out, your body will be blown apart by the natural energy!"
"How can this child be even more reckless than Jiraiya back in the day!"
Naruto flipped out of the oil pool, his entire body soaked from head to toe in thick crude oil.
He returned to the edge of the fountain and sat down. The next second, natural energy from all directions frantically surged into his body. The density of this energy was dozens of times greater than when it was previously applied to his hands.
Fukasaku's expression changed drastically. He quickly picked up the ruler that had fallen to the ground and rushed in front of Naruto. He prepared to scatter the natural energy about to go out of control inside Naruto's body.
But immediately afterward, he discovered with horror that this massive natural energy, upon entering Naruto's body, not only did not run amok, but was instead rapidly absorbed at an extremely stable rate.
The surface of Naruto's skin was wreathed in a faint halo of light. This was the materialized reaction of Senjutsu Chakra that was automatically activated when a large amount of natural energy poured in.
Meanwhile, Naruto's body maintained its normal skin tone and form, showing no signs of toadification whatsoever.