The world around him was pitch black. Nagi took out some electric lamps to illuminate his surroundings. The ground was as black as the void. The air was exceptionally stale; it had likely only been ventilated when the pot was used to seal the Eight-Tails or another enemy. At all other times, it remained sealed.
Anyone else might not have survived for more than a few hours, but for a scientist, this wasn't an insurmountable problem.
Nagi took out a storage scroll and released some drinking water. When traveling, food and water were essential.
Next, it was time to create oxygen.
With precise control, he used Lightning Release to split the water. It was common knowledge that the electrolysis of water (H₂O) using direct current produced hydrogen (H₂) and oxygen (O₂). The current passed through the water, forming hydrogen at the cathode and oxygen at the anode, with the volume of hydrogen being roughly double that of oxygen.
And just like that, the most critical survival issue—air—was solved. After collecting enough oxygen, he fashioned a simple oxygen tank from some materials. With his breathing problem temporarily resolved, it was time to figure out how to escape the seal.
He first tried a tentative Flying Thunder God jump. He discovered that the space, while seemingly endless, did have a limit. It was a closed loop. He could see the kunai he had left behind earlier. He tried to teleport within the space and found it was useless. This was a separate dimension. He could move around inside it, but teleporting to a coordinate in the outside ninja world was impossible. The moment he tried, a strange power would pull him back to his original spot.
Nagi looked at the wounds on his body and didn't dare to try again. The teleportation had clearly failed, and he was lucky to have only sustained some injuries. If half his body had been left behind in a spatial rift, he'd be royally screwed.
"The most fatal problem is that this place is constantly absorbing my chakra..." Nagi reached out to use the green light of the Palm Healing Jutsu on his wounds but found that the chakra consumption was ten times greater than it would be outside. He gave up on healing and simply treated the wounds with styptic powder and bandages.
He swallowed a few food pills to recover some chakra. Nagi was now certain of one thing: any ninjutsu exposed outside his body would have its energy rapidly absorbed by this space.
In other words, when his food, chakra, and oxygen ran out, he would be dead.
He had to find a way out. Could he break this Sage's treasure from the inside with a single, powerful blow? Obviously not. The Eight-Tails had been trapped in here and couldn't get out; otherwise, one Tailed Beast Bomb would have solved the problem.
"I probably won't even have to wait for my food to run out..." Nagi smiled bitterly. The space was devouring his energy. The chakra within his body was slowly draining away. Although the amount was small, at this steady rate, it would be gone in less than two days. He didn't have the powerful regenerative abilities of a Tailed Beast.
After some thought, Nagi decided to try another method. When Sun Wukong was trapped in the gourd, he had drilled a hole to get out. Nagi looked at the ground, raised his Nichirin Blade, and plunged it downward.
BOOM!
He followed up with a Monstrous Strength Fist, blasting a large hole in the pitch-black ground.
But then, something frustrating happened. The hole began to repair itself at an incredible speed, returning to normal in less than a few seconds. It made sense. If it could be dug through, the Eight-Tails would have escaped long ago.
"What do I do?" Nagi frowned, deep in thought. The Flying Thunder God required sensing a coordinate to teleport, but the Amber Purifying Pot was interfering with the process, interrupting his jumps. The mechanics of space were incredibly complex. He was lucky his first failed attempt had only resulted in minor injuries. Leaving half his body in a spatial rift was a truly terrifying prospect.
"No, there is another way. A way to move through space without needing a Flying Thunder God coordinate." Nagi looked up into the endless darkness of the space.
His Sharingan held another ability, one he rarely revealed: Mind Teleportation.
It was a special technique. It wasn't ninjutsu; it was a psychic ability. In other words, a power of the mind. As long as his mental power, his spiritual energy, was strong enough, he could teleport directly to a location. Chakra merely provided the energy for his body; the most crucial component was his spiritual strength.
In other words, it was like what was needed to awaken the Mangekyo Sharingan. The Mangekyo didn't require chakra to awaken, but a kind of spiritual power. It was just that for humans, the emotion of despair was often far stronger than any positive emotion. The so-called "three times stronger when you turn to the dark side" was a result of this.
But—Nagi wasn't sure how much power it would take to use Mind Teleportation from within the Amber Purifying Pot. This was an unknown world. Like the Kamui dimension, the Amber Purifying Pot seemed to exist in a separate dimension. The cost of teleporting from such an unknown place directly back to the ninja world was impossible to calculate. It was like in the final war, when Obito used Kamui to take Naruto to Kaguya's ice and lava worlds to save Sasuke. When teleporting between different worlds, no one could say for sure how far it was or how much energy it would consume.
Nagi touched the Yin Seal on his forehead. It was time to release it. With the chakra providing the energy and his spiritual strength fueling the Mind Teleportation, he should be able to escape this damned pot.
Damn you, Sage of Six Paths. I'll settle the score with you when I get out of here, Nagi thought, spitting viciously.
Just as he was about to release the Yin Seal and use the Ryumyaku's chakra, a voice suddenly echoed in his mind.
"Hey. If you do that, you'll definitely die. You might even leave half your body stuck in a spatial rift."
"You! I sealed you in the depths of my mind! How can you be out?!" Nagi was shocked. He had clearly used his Mangekyo to throw this part of himself into the recesses of his mind and bury it in a deep pit. How could it have gotten out?
"Heh heh. Call me White Ho. I quite like that character. Let's talk inside."
Instantly, Nagi was pulled into a mental world. This was the world of his own mind, a landscape of towering skyscrapers, like the modern city from his past life.
And there was White Ho—another him—dressed in casual clothes, sitting in front of a King of Fighters '97 arcade machine, playing a game.
"Heh heh. Theoretically, you can't seal me away, because I am you. The prison you lock me in is my own body. The only reason I haven't come out is because I don't want myself to have a split personality."
"You can think of me another way. I am your subconscious, the you in your dreams at night, while you are the you during the day. We are, in fact, one person, one soul. So, you don't want to die, and I don't want to die. Understand?"
"So, what are you planning to do?" Nagi asked calmly. This time, he didn't impatiently try to lock this dark side of himself away.
"Through my research on myself during this time, I've discovered something you might not believe."
"If you have something to say, say it. If you have to fart, just let it rip," Nagi said impatiently.
"Such an impatient one. Let me put it this way: the so-called dark side, the inner demon... severing them, as depicted in the Buddhist and Taoist novels and movies, is actually misleading. The truth is that the person, due to self-condemnation from their own morals and conscience, develops a split personality. What they really need to do is to merge with their dark side again, to become one person. To sever the inner demon, to eliminate the dark side of oneself, is essentially to discard a part of one's own soul. Do you understand now?"
"Even the dark side of yourself is a part of your soul. If you cut it off and throw it away, it may seem like your spirit has been elevated, but in reality, you have permanently severed a part of your soul. Your potential will forever be capped at that point."
Nagi was silent. What his dark side, White Ho, was saying... seemed to have some merit.
"Let me give you another example. If a high monk kills a mosquito, he has broken a commandment against killing. What if a baby kills a mosquito? Do you think the baby will develop a dark side? The answer is yes."
"And let's talk about Uchiha Madara. Was he dark? The entire ninja world probably thought he was a villain. But he never once doubted himself, never felt any self-condemnation or guilt from his own morals or conscience. He believed that what he was doing was right. Therefore, he would not give birth to an inner demon, let alone a dark personality."
"So, what are you trying to say? You want to merge with me again? Aren't you afraid I'll sever you?" Nagi asked curiously.
"I told you, I am you. Only people with split personalities would suspect they are two different people. And as it happens, I do not have a split personality."
White Ho laughed smugly, while Nagi looked at him with a strange expression. His own dark side was discussing split personalities with him.
"It's just like last time. The king and his mount, how about it? I will be the mount, and you will be the king. If we two become one, we might not only be able to easily jump out of this damned Amber Purifying Pot, but we might even awaken the Eternal Mangekyo Sharingan."
Eternal Mangekyo Sharingan...
Nagi fell silent. Although he had the White Zetsu cells and wasn't at risk of going blind, a higher-level Eternal Mangekyo would certainly be more powerful. At the very least, Nagi was sure that with an Eternal Mangekyo, he could manifest the final form of his Susanoo with ease. With a regular Mangekyo, even manifesting the second form was a struggle.
"Fine. Just this once. Never again."
The Nagi that was White Ho smiled. "There will be no next time. Once we cooperate, I might just disappear. To you, it might be a successful severing of your inner demon. To me, it is also a successful severing of my inner demon. Because to White Ho, the positive personality is also his inner demon."
"So, once we cooperate, the connection between our souls will be strengthened again, and we will very likely become one again. But we must both remember: we must learn from Madara. Whatever we do, we must never deny or condemn ourselves. Just fucking do it."
When Nagi emerged from his mental world, the pupils of his Mangekyo remained, but the rest of his eyes had turned one part white, one part black.
"Yin Seal, release!" +1
"Yin Seal, release!" +2