Katsuyu truly did not expect that Uchiha Jin would ask about this matter.
However, after a long while.
It still let out a faint sigh, and then began to explain slowly in a low voice.
"Shikkotsu Forest..."
"Actually, this is a beautiful name from only the last few hundred years. In reality, its original name was—Forest of Corpses!"
"Buried here are countless gods, Onmyōji, yōkai, priests, and shrine maidens from the Old Era..."
"The war back then was too terrifying. At that time, I had just gained sentience. The earliest images in my memory are of a group of gods and experts using their means to directly sever this region and completely exile it into a different dimension."
"So Chakra actually finds it very difficult to exist here."
"This is also the real reason why the successors of the other two Great Sage Regions frequently go to Mount Myōboku and Ryūchi Cave to practice, while the successors of Shikkotsu Forest only summon me to the Ninja World and basically never come to Shikkotsu Forest."
"Because here, one cannot cultivate Chakra!"
"For this same reason, I have rarely contracted new successors over the years."
"It's just too boring staying here, so I still keep one successor just so my clones can go to the Ninja World continent. Staying here all year round is simply too lonely."
Katsuyu spoke eloquently, its voice still sweet.
However, Uchiha Jin could still sense an indescribable solitude, loneliness, and coldness from its gentle words.
Thinking about it carefully, it was quite normal!
Mount Myōboku and Ryūchi Cave are inhabited by entire clans, but Shikkotsu Forest has only one living being, Katsuyu. Those large and small slugs seen everywhere are nothing more than clones it split off to pass the time.
Such prolonged solitude is something any normal living being would likely find unbearable.
Thinking of this, he relaxed his guard quite a bit.
He began to ponder Katsuyu's words, and combining them with the original work he had read in his previous life, he roughly outlined the silhouette of the Old Era Katsuyu spoke of.
Gods, Onmyōji, yōkai, priests, shrine maidens...
These professions he was familiar with from his past life were likely the ones that originally existed on this planet before the arrival of the Ōtsutsuki.
But what about now?
Only a few legends of gods remain: the King of Hell summoned by Nagato's Rinnegan, Hidan who believes in the Wicked God, and that Shinigami who looks like an Ōtsutsuki and whom he suspected to be Hamura...
What is revealed externally are all just empty shells, or more accurately, they seem like mere husks.
Are these gods dead or alive?
No one knows, and the original work never explained it.
As for Onmyōji, yōkai, shrine maidens, priests, and the like, they haven't even been heard of in the current Ninja World, and not even a shred of legend has been left behind.
Originally, Uchiha Jin had always thought that the bodies of these Old Era experts had long ago been fed to the God Tree rooted in the Ninja World by the two Ōtsutsuki, Kaguya and Isshiki...
He hadn't expected this.
There were truly powerful experts among the gods of the Old Era, capable of preserving the bones of these deceased and using their methods to exile this piece of land to a different dimension.
"So, that's how it is!"
"However, it is understandable. After all, those Ōtsutsuki are indeed not people an ordinary person can oppose."
"What I'm curious about now is, what about Mount Myōboku and Ryūchi Cave?"
Uchiha Jin pondered for a moment, and then could not help but have a question.
Since the Shikkotsu Forest Sage Region was created by the Old Era gods, what was the situation with the other two Great Sage Regions?
Meanwhile, on the other side.
Before he could figure out this problem, Katsuyu's voice began to sound surprised.
"Lord Jin actually knows about the Ōtsutsuki?"
"Yes, I know a little."
Uchiha Jin nodded.
He had no interest in explaining to Katsuyu, and instead asked directly, "Is the situation of those two Sage Regions, Mount Myōboku and Ryūchi Cave, any different from Shikkotsu Forest?"
Katsuyu let out a soft sigh and fell into silence.
It truly had not expected Uchiha Jin to know about the Ōtsutsuki.
But—how is that possible?
Since Hagoromo and Hamura passed from the stage, no Ōtsutsuki had walked the Ninja World.
Especially since the humans of the Ninja World do not have the habit of recording history, combined with years of constant warfare, the information occasionally passed down consists of only a few words about the Six Paths Sage.
So it really couldn't figure out where Uchiha Jin learned of this.
However.
This gave it a faint understanding of why Uchiha Jin's actions to unify the Ninja World had become so slow and complicated; he was likely guarding against that person in the Pure Land.
But, never mind.
Anyway, it didn't have much to do with it, so after thinking for a bit, it let out a soft sigh and said, "There are some differences from Shikkotsu Forest, but they were also created by the Old Era gods."
"However, their purposes are different!"
"Shikkotsu Forest's purpose is as a tomb, to commemorate the gods and experts who died back then, and on the other hand, it is a place for living beings to prepare to become stronger."
"Mount Myōboku has the largest area and is a place for all living beings to survive."
"As for Ryūchi Cave, its purpose is a place for training and slaughter!"
"The slaughter during the Old Era was too fierce. After the gods and experts realized the situation was beyond salvation, they concentrated all their power to tear these three continental fragments from the planet and used great power to exile them into a different dimension."
"The three continents each had their own role, leaving a piece of soil for living beings to survive."
"Mount Myōboku ensures the basic survival of all spirits, Shikkotsu Forest serves as a place of inheritance and memorial where all spirits can come to inherit techniques, and Ryūchi Cave serves as a place for slaughter and trials."
"Once their strength was great enough, they would gather all their power to strike back at their homeland and declare war on those two Ōtsutsuki."
"But, unfortunately."
"Gamamaru of Mount Myōboku was the first to defect. He took the initiative to contact and accept Chakra, eventually choosing to join forces with the Ōtsutsuki and ultimately setting a trap to wipe out the remaining Old Era experts and gods."
"Later, after Kaguya turned against Hamura and Hagoromo, Gamamaru joined forces with the two brothers to seal Kaguya, and after that, it gradually became one of the Three Great Sage Regions."
"Those toads have the best relationship with Hagoromo, so naturally, they have the most frequent contact with the humans of the current Ninja World."
"Seeing this, the White Snake Sage of Ryūchi Cave also began to actively embrace Chakra, thus becoming one of the current Three Great Sage Regions."
"However, unlike Mount Myōboku, the White Snake Sage is very wary of the Ōtsutsuki. Those snakes just hide in Ryūchi Cave and have never chosen to contact Kaguya or the other Ōtsutsuki."
"Because the Three Great Sage Regions are in a different dimension, unless they actively open an entrance, even the Ōtsutsuki cannot find them. Therefore, the Ōtsutsuki cannot find Ryūchi Cave either."
"Shikkotsu Forest is the most special!"
"Because so many Old Era gods and experts are buried here, it is very difficult for Chakra to circulate in this place. This is the real reason why Shikkotsu Forest's Sage Art is rumored to be the most difficult to master."
"Because Shikkotsu Forest has no Sage Art at all. That was just something I did because I was too bored over the long years; I randomly obtained some Chakra from the outside and fused it with the divine arts of the Old Era gods and natural energy, creating a little mixed-up thing."
"It's just that as time passed, and since we were all part of the Three Great Sage Regions, it was named Senjutsu Chakra."
"In any case, over such a long time, only Lord Hashirama has been able to truly master it."
"Other contractors, including Lady Tsunade, let alone practicing Senjutsu Chakra, basically never come to Shikkotsu Forest in their entire lives. After all, this place is very unfriendly to Chakra users."