"Senior Shinku, it's still early. Could you start teaching me genjutsu now?" Even after receiving all of Yūhi Shinku's genjutsu materials, Kōki did not leave right away. With a living, breathing genjutsu teacher right in front of him, there was no need to go back and struggle through the writing on the scrolls.
Yūhi Shinku smiled at Kōki's request. "No problem."
To be honest, Yūhi Shinku was very satisfied with today's trade. First, he had obtained the precious taijutsu, Superhuman Strength, which could improve his strength. Second, he had found someone to carry on his legacy.
That was right. Yūhi Shinku already regarded Kōki as his successor in genjutsu. Of course, this was his own one-sided idea. He wanted to see how far Kōki could develop in genjutsu after inheriting his teachings.
"Kōki, what do you think genjutsu is?" Yūhi Shinku began by asking about Kōki's understanding of genjutsu. He intended to start with the fundamentals and gradually work his way up.
Hearing Yūhi Shinku's question, Kōki also settled into a learning mindset. He lowered his head and thought briefly before answering, "Genjutsu refers to techniques that use chakra to attack an enemy's five senses, with the aim of confusing them."
Kōki's explanation made Yūhi Shinku nod. He had trusted that Kōki would know these genjutsu basics. Then he continued, "Then do you know what genjutsu can achieve at its highest level?"
This time, Yūhi Shinku's question had some depth. In the shinobi world, genjutsu was generally used as a supplementary skill in battles between ninja. Very few ninja made genjutsu their main focus.
As such, no one knew what heights genjutsu could ultimately reach. But Kōki was different. He had watched 720 episodes of Naruto, and his understanding of the heights of genjutsu could be called the greatest in the shinobi world.
Kōki perked up and said with a serious expression, "Senior Shinku, I believe the heights genjutsu can reach are limitless." His very first words stunned Yūhi Shinku.
"The foundation of genjutsu is attacking an enemy's five senses, but if developed to a higher level, it can control those senses. Everything the enemy hears, sees, smells, touches, and tastes will be under your control. You could even deceive someone's consciousness through their five senses, making the enemy injure themselves or even die."
"If genjutsu develops even further, or rather, develops toward its essence, yin release chakra, I think it could control someone without affecting their self-awareness. It might even transform dreams into reality and reality into dreams, and create things from nothing."
"I've heard that the Uchiha Clan's Sharingan possesses this kind of genjutsu that goes beyond the ordinary."
After hearing Kōki's words, Yūhi Shinku's face was full of surprise. He had not expected Kōki to see genjutsu as something so powerful.
From what Kōki had just said, Yūhi Shinku could see how highly he regarded genjutsu. However, he thought that while some of the advanced genjutsu Kōki described could be achieved, others would be very difficult to realize.
Manipulating the five senses, for example-such genjutsu already existed. There was a clan in the village with a kekkei genkai of this kind, but unfortunately, no one had awakened it at present.
As for the Uchiha Clan's Sharingan genjutsu that Kōki mentioned, he had never seen it, so he had no right to comment.
But even if the kind of genjutsu Kōki described really did exist, only the Uchiha Clan's Mangekyō Sharingan might be capable of it. An ordinary Sharingan could not cast such genjutsu.
What Yūhi Shinku did not know was that there was an ultimate genjutsu even an ordinary Three-Tomoe Sharingan could perform: Izanagi or Izanami, genjutsu cast at the cost of a Sharingan.
It was only natural that Yūhi Shinku would not think of it. How could an ordinary person imagine that genjutsu could transform dreams and reality? If Kōki had not known that the Sharingan's ultimate forbidden technique, Izanagi, also fell within the category of genjutsu, he would never have imagined that genjutsu could go so far either. However, he knew that the Sharingan's ability to use such genjutsu was still related to its innate ocular power.
Almost everyone knew that the Uchiha Sharingan's power came from its ocular power, but very few people explained the essence of that ocular power.
But Kōki believed that all techniques, however varied, followed the same fundamental principles and were formed from combinations of the seven chakra natures.
Even the ocular power of the Uchiha Clan's Sharingan, which seemed to stand apart from the seven natures, ultimately resulted from combining yin release chakra with spiritual energy.
It was simply that members of their clan possessed the Sharingan, allowing them to bring out the effects of yin release more easily than ordinary people, and with greater power.
Kōki had grounds for thinking this way. First, he recalled the overview of Yin Release and Yang Release from Naruto in his previous life. Yin Release was the power of yin, sourced from the spiritual energy that governed imagination, creating form from nothing. Yang Release was the power of yang, sourced from the physical energy that governed life, breathing life into form. This explained that Yin Release was the foundation of creating things from nothing.
Second was Tobirama Senju's description of the Sharingan in the original work, calling it the eye that reflected the heart.
Moreover, quite a few facts supporting these two views had appeared in the original work.
In the original work, Madara Uchiha could use Susanoo, the ultimate secret of the Mangekyō Sharingan, without any eyes. Kakashi, who had already lost his Sharingan, could still use the complete Susanoo and even Kamui Shuriken.
The original anime presented these phenomena as help from the spirits of the dead. But in the real Naruto world, Kōki could only explain them as the effects of yin release chakra and spiritual energy.
As for Madara Uchiha being able to use Susanoo without eyes, Kōki believed that Madara had completely mastered the yin release chakra fundamental to activating Susanoo.
Kakashi, meanwhile, had activated Susanoo by using the chakra Obito left him. Kōki guessed that after Obito successfully broke through to the Six Paths level, his chakra changed, gaining a measure of Six Paths-level yin release nature. This was what allowed Kakashi to use Susanoo even after Obito's death.
These were the grounds that made Kōki believe yin release chakra, the essence of genjutsu, had an extremely high ceiling and was worth exploring in depth.
"I never expected you to think so highly of genjutsu. To be honest, even after practicing genjutsu for so many years, I've only ever thought about using it to control enemies and defeat them. It never occurred to me that genjutsu could transform illusion into reality and reality into illusion, or create things from nothing."
"Unfortunately, it's already too late for me now." Kōki's vision for genjutsu made Yūhi Shinku realize that there were still many sights along the path of genjutsu he had never seen. Unfortunately, by the time he realized it, it was already too late.
He understood that every one of those genjutsu Kōki described involved a profound application of Yin Release, the essence of genjutsu. Unfortunately, he had been exposed to Yin Release for too short a time. Even after studying genjutsu for so long, he had only scratched the surface of Yin Release.
He had never delved deeper into Yin Release. Or rather, he lacked the talent to delve deeper into it. He could feel that his talent for genjutsu could only take him this far.
At that thought, Yūhi Shinku felt somewhat unwilling to accept it. But looking at Kōki in front of him and Kurenai beside him, he found some comfort. What he could not accomplish himself, he could have his daughter and disciple accomplish for him.
(P.S. I posted this a little hastily, so I made a few minor revisions.)