It was night, and Orochimaru was deep in thought at his hideout. Had he truly been completely betrayed?
He had been trying to summon Manda for the past few days, but there hadn't been even the slightest response.
Just then, a voice called from outside the door: "Lord Orochimaru, I have arrived."
"Ah, Setsuna-kun. Please, come in."
Orochimaru observed the young man who entered. "It seems the Chunin Exams are starting soon. Setsuna-kun, do you have time to visit me? Shouldn't you be doing more preparation?"
Setsuna replied casually, "It's just the Chunin Exams. There's nothing to prepare for."
"Heh-heh. With your strength, Setsuna-kun, the Chunin Exams are certainly nothing to worry about. But what about the unforeseen events that might occur during the exams?" Orochimaru said sinisterly. "Holding a joint Chunin Exam at such a sensitive time makes it hard not to suspect Sunagakure's intentions."
"I'm just a low-ranking Genin. That kind of matter isn't for me to worry about," Setsuna said humbly.
"A 'low-ranking Genin,' you say?" Orochimaru couldn't help but chuckle. "By the way, Setsuna-kun, have you summoned Manda recently?"
"No, I haven't," Setsuna stated honestly. His last summoning of Manda had been a year ago, so it certainly wasn't "recent."
"I see. Snake summons truly are untrustworthy, then." Seeing that Setsuna didn't appear to be lying, Orochimaru couldn't help but sigh.
Setsuna's eyes flickered. "Speaking of snake summons, Lord Orochimaru, I heard from Minato-sensei that Mount Myōboku has a Sage Art lineage. Does Ryūchi Cave have one as well?"
Minato hadn't actually told him that, but it didn't matter. He just needed him to serve as a convenient background character.
"Oh? Is Setsuna-kun interested in Sage Arts?" Orochimaru asked.
"Just a little curious," Setsuna answered truthfully.
He wasn't actually interested in the Sage Arts itself, but rather the various power boosts that Sage Mode provided.
"Practicing the Sage Arts is very dangerous. Once you are overwhelmed by Natural Energy, you become one with nature," Orochimaru sighed. Even Jiraiya could learn the Sage Arts, but he personally lacked the aptitude.
In his view, it was entirely because his mind was too restless, which went against the 'stillness' required for Sage Training.
Jiraiya, on the other hand, while normally acting like he had ADHD, could find inner peace when practicing the Sage Arts.
"Natural Energy?" Setsuna recalled what Boss Slime had said. "Does only Natural Energy exist in nature? Could there also be Chakra?"
Orochimaru looked at Setsuna in surprise, then narrowed his eyes and asked, "Why would you think that? The Ninja Academy should have already taught you that Chakra is refined from physical and spiritual energy."
"It's because I encountered the Cloud Village's Eight-Tails Jinchūriki recently, and it left me very confused. Rumors say that Tailed Beasts are the physical manifestation of Chakra, but if they cannot refine Chakra, then logically, every time a Jinchūriki borrows their power, the Tailed Beast should be weakened. The reality, however, is completely the opposite. So, I suspect their Chakra is replenished from the natural world."
"There are fewer and fewer shinobi willing to think like you, Setsuna-kun," Orochimaru remarked with emotion, his expression becoming serious. "To answer that question, we first have to clarify one thing, Setsuna-kun: do you think Chakra remains in the Ninja World after a shinobi uses a Jutsu or after a person dies?"
Setsuna answered earnestly, "I can't say for sure, but I believe at least a portion of it does."
In his opinion, Chakra was just data carrying the user's information, much like the Ōtsutsuki Clan's Karma.
The Ōtsutsuki Clan's Karma turns their own data into a copy that they inject into another person. When the vessel's body is completely replaced by the Ōtsutsuki's data, the Ōtsutsuki is resurrected.
The residual Chakra of Asura and Indra remains in the Ninja World, constantly reincarnating. Their Chakra might not reach the same level as the Ōtsutsuki, but it's very close.
Also, when Dan Katō was released from the Edo Tensei, he was able to pass his Chakra to Tsunade. Obito was able to give his eye to Kakashi after his death. These things all seem to indicate that Chakra doesn't just instantly dissipate after death, but can still be transferred.
Orochimaru stated, "You know about plastic, that product of technology, right? That synthetic material is very difficult to break down in nature. Chakra is the same. As a secondary energy synthesized from physical and spiritual energy, it takes a very long time to decompose. The stronger the shinobi, the harder their Chakra is to break down."
(You can tell from the episode where Kakashi and the Third Hokage visit Naruto's house that potato chip bags have plastic.)
"For the natural world, of course, the sooner the Chakra decomposes, the better. But the Ninja World coincidentally has creatures like the Tailed Beasts. They continuously absorb Chakra and continuously use Chakra, causing Chakra to constantly pile up in the Ninja World. These Tailed Beasts also grow stronger and stronger."
Setsuna was inwardly shocked. That seemed right—the Nine-Tails looked vastly different in its youth than it does now, especially the Seven-Tails, Chōmei, which transformed from an insect pupa in its youth into a flying rhinoceros beetle.
The fact that the Tailed Beasts, which are aggregations of Chakra, are growing, doesn't that prove they are constantly absorbing Chakra?
"Did the Sage of Six Paths create the Tailed Beasts to purify the Chakra and keep it from decomposing?"
Setsuna couldn't help but think this way. After all, the Sage of Six Paths' claim that "the Tailed Beasts were created to trust and help humanity" is utterly unbelievable. For a thousand years, the Tailed Beasts have been viewed as symbols of disaster and have never lived peacefully with humans. Was the Sage of Six Paths just watching the whole time?
Also, in the final battle, the Sage of Six Paths summoned the Kage of each village. Before the first Kage, there must have been powerful shinobi from nearly a thousand years ago, but the Sage of Six Paths didn't summon them.
Now, it seems those strong individuals' residual Chakra might have been "cleansed" by the Tailed Beasts, losing the information of their original self.
"As expected of Lord Orochimaru. While everyone else is busy fighting for power, you are already exploring the fundamental nature of the Ninja World," Setsuna genuinely praised him.
"Heh. I only discovered the true nature of infinite Chakra while studying the Second Hokage's Edo Tensei," Orochimaru felt flattered. This was indeed his greatest achievement, and given his usual composure, he couldn't help but get a little carried away.
"Edo Tensei?" Setsuna raised an eyebrow. Was that something he should be saying out loud?
Orochimaru was suddenly startled, realizing he had just gotten so carried away that he let something slip.
"Should I silence him?" A fierce look flashed in Orochimaru's eyes, but then he remembered the battle records he had heard about Setsuna. "Forget it. I don't think I can beat him."
"Ahem. I was researching that jutsu so that Konoha could achieve victory. In any case... ahem, let's return to the original topic. Precisely because Natural Energy contains an increasing amount of Chakra impurities, it is becoming more and more difficult to separate and absorb the pure Natural Energy. That first step is extremely perilous. I advise you not to attempt it without absolute confidence."
Setsuna was deep in thought. "I heard from Minato-sensei that Sage Mode Chakra is refined by mixing Natural Energy, physical energy, and spiritual energy at a 1:1:1 ratio. Since the Natural Energy is mixed with Chakra, is it possible to alter the ratio directly during absorption to refine it?"
"Theoretically, yes, but no one other than the Tailed Beasts can do it," Orochimaru scoffed, shaking his head. "Absorbing pure Natural Energy is already very dangerous. If you absorb impure Natural Energy, you will be instantly overwhelmed by it."
"I understand," Setsuna nodded, then spoke in his mind: "Boss Slime, my best friend, I leave the heavy task of refining Sage Mode Chakra to you from now on."
Boss Slime was speechless. "Who do you think I am? Your personal employee?"
"Oh? I thought this would be easy for an Emperor of the Universe. It's fine, though. If you can't do it, no worries. After all, you aren't even from our universe..." Setsuna sighed dramatically.
Boss Slime slammed the table, figuratively. "Let me be clear: I am not doing this because you tried to provoke me. It's just that you're right; this sort of thing is indeed very easy for me, the Emperor of the Universe. I'm merely bestowing some power upon you as an act of charity."
Setsuna praised him sincerely: "Truly worthy of the great Emperor Slime! Such a strong personality!"