Mount Myoboku.
Naruto sat in deep meditation under a colossal leaf, sensing the faint, ethereal natural energy surrounding him. Nearby, Jiraiya and Great Sage Fukasaku watched over his training while conversing.
This was clearly not Naruto's first such session.
The outbreak of the Great Ninja War had instilled a sense of urgency in Jiraiya. Beyond refining Naruto's foundations in Taijutsu and Ninjutsu, he had brought the boy to Mount Myoboku to master Sage Mode. During their time at the Alliance headquarters, they made frequent use of Summoning Jutsu to slip away to the mountain for these secret training sessions.
Noticing the orange pigment gradually forming around Naruto's eyes, Fukasaku nodded with satisfaction. "This kid's talent is even higher than his father's!"
Jiraiya sighed with emotion. "Yeah. Even I didn't expect him to absorb natural energy at such a rapid pace."
"If he continues at this rate," Fukasaku added, "it won't be long before he fully masters Senjutsu."
Jiraiya's expression turned somber. "I'm afraid time is a luxury he no longer has."
"Oh?" Fukasaku looked at Jiraiya with concern. "Has there been a new development in the war?"
Jiraiya shook his head. "The Akatsuki are still recuperating, and 'Upper Rank One' has vanished without a trace. The intensity of the war has leveled off over the past two weeks. However, I have a gut feeling... this is merely the calm before the storm."
Fukasaku nodded slowly, looking as though he wanted to say something but was hesitating.
Noticing the Sage's internal conflict, Jiraiya quickly asked, "What is it?"
Fukasaku sighed and spoke gravely. "The Great Toad Sage had a new prophecy recently."
Jiraiya froze for a moment before asking urgently, "What was it? Is it about the Child of Prophecy?"
Fukasaku slowly shook his head. "This prophecy is even more blurred than the ones before. Even the Great Toad Sage himself cannot describe it clearly. He can only faintly sense an extremely evil force approaching the Ninja World."
Confusion clouded Jiraiya's face. "An evil force?"
Fukasaku continued, "In his vision, the Great Toad Sage saw the Ninja World shattered... and the final spark of light being extinguished."
Jiraiya gasped. "How can that be?!"
"A prophecy is merely a glimpse of a possible future," Fukasaku explained. "The Great Toad Sage has simply sensed that the world has the potential to head toward such an end."
For the first time in a long while, a look of genuine panic crossed Jiraiya's face. He had always been a firm believer in the Great Toad Sage's visions; otherwise, he wouldn't have spent decades wandering the world in search of the 'Child of Prophecy' who could save it.
Hearing of the potential destruction of the Ninja World filled him with both terror and self-reproach. He couldn't help but ask, "Is it because I haven't found the Child of Prophecy yet?"
Fukasaku shook his head—not as a 'no', but because he truly didn't have the answer.
Left to his own thoughts, Jiraiya muttered, "Who could this evil force be? Nagato?"
He quickly shook his head. He knew Nagato. Even though their ideologies had diverged, he firmly believed Nagato was trying to protect the world in his own way; he would never intentionally destroy it.
"Could it be 'Upper Rank One'?" Jiraiya suggested.
In his mind, only those two posed a significant threat. If it wasn't Nagato, it had to be 'Upper Rank One'. Yet, despite the terrifying power shown during the 'Infinity Castle' battle, it didn't seem likely that one individual alone possessed the power to destroy the entire Ninja World.
Seeing Jiraiya's struggle for an answer, Fukasaku said, "I cannot give you an answer, for even the Great Toad Sage does not know what this destructive force actually is."
Jiraiya wasn't ready to give up. "Is there no clue at all?"
Fukasaku's expression turned pained. "The Great Toad Sage said that merely by attempting to cast his gaze toward that evil, he felt an instinctive, primal shudder."
Jiraiya's face paled. "That... how is that possible?"
"That is all I know," Fukasaku said.
"Then how do I save the world?" Jiraiya asked desperately. "If I find the 'Child of Prophecy,' can we avoid this fate?"
Fukasaku thought for a long while before saying slowly, "In this prophecy, the Great Toad Sage did not mention the 'Child of Prophecy.' However... he repeatedly mentioned 'the Light'."
"The Light? What does that mean?"
"I cannot say for certain," Fukasaku explained. "But the Great Toad Sage said that 'the Light' is the strength that allows the Ninja World to hold on until the very end. Only when it is extinguished does the world truly fall into ruin. Therefore, 'the Light' may be the key to salvation."
Jiraiya fell into deep thought. 'Light' was an incredibly vague concept. It could represent a person, an organization, a specific will, or even a spirit. He racked his brain, but he could not determine what the 'Light' in the prophecy represented.
Just then, Naruto stood up in the distance and shouted, "Pervy Sage! Sage Fukasaku! I've finished absorbing the natural energy!"
With Naruto's interruption, the two stopped their discussion.
Walking over to the boy, Fukasaku marveled, "The speed at which you absorb natural energy is incredible, simply unbelievable. Naruto, how did you do it?"
Naruto scratched his head. "Was it supposed to be hard?"
Jiraiya scoffed. "Don't be ridiculous. Do you know how many geniuses get stuck on this single step? Even your father, Minato, wasn't as fast as you."
Suddenly, a spectral figure floated out of Naruto's body. Crossing its arms with a smug expression, it said, "It's all thanks to me!"
This figure was, of course, the spirit of Menma residing within Naruto.
Naruto, with his Uzumaki bloodline and status as a Jinchuriki, already had a massive chakra capacity that made absorbing natural energy easier. With Menma's assistance, his efficiency was essentially doubled—a fact that continued to stun both Jiraiya and Fukasaku.
Sensing and absorbing natural energy was only the first step of Senjutsu. The next was to merge it with one's own chakra in a precise ratio to create the more powerful and mysterious Sage Chakra. With the guidance of two masters, this step was not difficult for Naruto.
In the training that followed, Naruto continued to display an extraordinary aptitude for Senjutsu, leaving his teachers in a state of constant wonder.