"I've actually been in contact with Sage Mode for a long time, but I still haven't mastered it yet..." Jiraiya scratched his head and spoke.
"The Sage Mode you're talking about is something I don't know. Even if I wanted to teach you, I can't..." Tsunade also spoke up.
"Does Shikkotsu Forest not have Sage Mode? As one of the three great sage regions, it must have sage arts, right?" Uchiha Ryun frowned.
Tsunade fell silent for a moment, then sighed and explained:
"Of course, there is sage arts inheritance. But to learn the sage arts of Shikkotsu Forest, one must possess an extremely abnormal amount of chakra. I don't meet this condition..."
"The only one who has mastered Shikkotsu Forest's sage arts so far is my grandfather."
"The First Hokage? He mastered Shikkotsu Forest's Sage Mode?" Orochimaru couldn't help but ask curiously.
"Yes. To learn Shikkotsu Forest's sage arts, you need the approval of the Great Slug Sage. I wanted to learn it too, but I don't have my grandfather's talent. The Great Slug Sage advised me to give up, saying I couldn't learn it, and that it was too dangerous..."
"Shikkotsu Forest's Sage Mode requires one's own chakra to forcibly suppress natural energy."
Tsunade truthfully recounted her experience and also revealed an important piece of information.
"To learn Ryūchi Cave's Sage Mode, you must first be bitten by the White Snake Sage. It injects natural energy into the human body, achieving the effect of mastering Sage Mode..."
Uchiha Ryun proactively shared information about Ryūchi Cave's Sage Mode.
"Biting to inject natural energy? What a strange method... In Shikkotsu Forest, the medium for sensing natural energy relies entirely on the slug's attachment. The slug temporarily replaces the host to absorb natural energy." Tsunade continued to explain what she knew.
Seeing that Tsunade and Uchiha Ryun had openly shared information about their respective sage regions, Jiraiya also felt it would be inappropriate to keep hiding things:
"The temporary medium for the toad clan to absorb natural energy is a special toad oil from Mount Myōboku. Applying this oil to the body allows natural energy to rapidly flow into the human body."
"So, slug attachment and applying toad oil—these mediums are only temporary? Simply to help people sense natural energy faster?" Uchiha Ryun suddenly asked a question.
He felt that the reason Ryūchi Cave's Sage Mode caused serpentification was closely related to being bitten by the White Snake Sage.
Perhaps it was possible to master Sage Mode without being bitten, but the prerequisite was sensing natural energy on your own and absorbing it into your body.
As a transmigrator, Uchiha Ryun actually knew most of the information Jiraiya was aware of. However, he had no access to Mount Myōboku. Without the help of toad oil or toads to monitor and control the unstable natural energy, even if he knew some tricks, he couldn't learn Sage Mode.
This ability wasn't something that could be learned just by talking about it. Natural energy was too dangerous. Without the personal guidance of a sage from the sacred regions, it was nearly impossible to learn Sage Mode. Blindly attempting it could easily lead to death.
"You could say that... The first major hurdle of Sage Mode is sensing natural energy. Without a medium, it's extremely difficult for ordinary people to sense natural energy. Moreover, it's hard to experience the feeling of natural energy entering the body..."
Jiraiya explained why a medium was necessary.
"But I think that while the medium helps, it also hinders. The risks of Sage Mode might also be caused by the medium..." Uchiha Ryun voiced his opinion.
"What! That can't be possible!!!" Jiraiya exclaimed, finding Uchiha Ryun's idea too unbelievable.
"It's entirely possible. Ryūchi Cave's Sage Mode relies on the White Snake's 'venom injection.' Whether successful or not, it leads to a transformation toward a non-human form. Mount Myōboku's Sage Mode should be similar, right? I'm guessing it's toadification..."
As soon as Uchiha Ryun said this, Jiraiya's eyes widened: "You're absolutely right... Mount Myōboku's toad oil does cause toadification, even petrification..."
"Then the question arises: if you don't rely on these mediums, or even enter the three great sage regions, what kind of changes will the human body undergo after absorbing natural energy from the outside world?"
"Will it be serpentification? Toadification? Slugification? Or will there be no changes at all?"
Uchiha Ryun asked this question, which was also the one he cared about the most.
The three of them were stunned. They hadn't even mastered Sage Mode yet, so they obviously couldn't answer this question. In fact, they had never even thought about it.
The truth was that the three great sage arts weren't originally created for humans. The so-called side effects were only applicable to humans.
The sage arts truly suitable for humans might not have been created yet, or perhaps they once existed but the inheritance was lost.
From Jiraiya, Uchiha Ryun learned that without relying on a medium, and without the dense natural energy of the three great sage regions as an aid, an ordinary person with average talent would need at least twenty to thirty years to sense natural energy.
And this was only possible under the condition of long-term meditation and mental cultivation.
To use spiritual will to absorb natural energy from the outside world into the body would take an ordinary person at least another eight to ten years.
Combining natural energy, spiritual energy, and physical energy to form traditional senjutsu chakra, and then accumulating enough of it, would inevitably require a significant amount of time and effort.
It wasn't impossible for a person to cultivate into a sage on their own, but by the time they succeeded, they might already be old.
Once the body aged, they would face the dilemma of having sufficient natural energy and spiritual energy but insufficient physical energy. Producing senjutsu chakra would then become extremely difficult.
Thus, a lifetime of cultivation might end in failure...
The average lifespan in the ninja world was less than fifty years. During wartime, this average was even lower. Who would be willing to spend their entire life cultivating sage arts?
It was understandable that no one had created a sage art suitable for human cultivation, especially when chakra was so prevalent.
When chakra power could be cultivated so easily, who would bother with the arduous task of comprehending sage arts?
Jiraiya's words left Uchiha Ryun deeply frustrated. Mastering Sage Mode without relying on a medium was far too difficult.
His contracted sage region was Ryūchi Cave. Learning Ryūchi Cave's sage arts meant being bitten, which would inevitably lead to serpentification (or draconification), turning him into something neither human nor serpent.
And that was only if he succeeded. Failure meant being eaten—though given his relationship with the Black Dragon, he might not end up as food...
But the mere cost of being bitten and transforming into a serpent (or dragon) was something he couldn't accept, even though he deeply coveted the power of a sage...
As for abandoning Ryūchi Cave and turning to Mount Myōboku, he was unwilling. After all, he had worked hard to subdue the powerful Black Dragon, and things couldn't always go as he wished.
Jiraiya's summoning contract wasn't something he could just sign, and Mount Myōboku's sage arts weren't something he could learn just because he wanted to.
Forget it. I'll decide whether to enter the cave and learn sage arts after the war is over...
For now, Uchiha Ryun suppressed his longing for power.