Chapter 406: Necessary Conditions

Chapter 406: Chapter 406: Necessary Conditions

Setting the Sage of Six Paths aside, in the original timeline, only one and a half pairs of Rinnegan had ever appeared in the shinobi world.

Of those, Sasuke’s single Rinnegan had evolved only after the Sage of Six Paths bestowed his Yin Power upon him. It was essentially a gift from the Sage of Six Paths, making it both extremely difficult to replicate and of little value as a reference.

Therefore, the only method of evolving the Rinnegan truly worth Hyuga Kagami studying was Uchiha Madara’s.

Madara’s Rinnegan had emerged after he obtained the Eternal Mangekyō Sharingan and successfully transplanted First Hokage cells into his body, achieving a perfect fusion between his own Yin Release and the First Hokage’s Yang Release.

In other words, judging from Madara’s example, the Eternal Mangekyō Sharingan representing Yin Release and the First Hokage’s cells representing Yang Release appeared to be the prerequisites for evolving the Rinnegan.

However, there was another factor that had to be considered.

Uchiha Madara was the reincarnation of ōtsutsuki Indra, while the First Hokage, Senju Hashirama, was the reincarnation of ōtsutsuki Asura. Within their bodies existed the chakra of Indra and Asura—chakra so extraordinarily powerful that it had continued reincarnating for a thousand years.

That raised an absolutely crucial question Hyuga Kagami needed to answer:

Was the chakra of ōtsutsuki Indra and ōtsutsuki Asura itself necessary to evolve a pair of Rinnegan?

That was precisely what Hyuga Kagami’s current experiment was intended to determine.

Through Shisui’s transplant surgery, he intended to uncover exactly what the necessary condition for evolving the Rinnegan truly was.

Was it the perfect fusion of an Eternal Mangekyō Sharingan with First Hokage cells?

Or was it the perfect fusion of ōtsutsuki Indra’s chakra with ōtsutsuki Asura’s chakra?

That was also the main reason Hyuga Kagami had gone to such extraordinary lengths, filling the entire operating room with all kinds of monitoring equipment.

If the necessary condition turned out to be the former, then Hyuga Kagami was confident that he could cultivate a pair of Rinnegan himself.

If the necessary condition was the latter—if it involved the chakra of ōtsutsuki Indra and ōtsutsuki Asura, those two ghosts who had been reincarnating for a thousand years—then Hyuga Kagami would have to proceed with extreme caution.

After all, the father of those two ghosts, the Sage of Six Paths, was still silently watching over the entire shinobi world.

Whether he would allow someone to set their sights on his two sons’ chakra, or whether he would permit a third pair of Rinnegan to appear in the world, was impossible to say.

Of course, there was another possibility.

Both sets of conditions might be necessary for evolving the Rinnegan, with neither one being dispensable!

Pulling back his wandering thoughts, Hyuga Kagami changed into surgical clothes and sterilized all the surgical instruments. Then, with perfect calm, he began the eye transplant surgery on Shisui, who was lying on the operating table.

After implanting the Eternal Mangekyō Sharingan into Shisui’s eye sockets, Hyuga Kagami asked, "How does it feel?"

Shisui took a moment to adjust before saying with some confusion, "I don’t know why, but these eyes feel strangely familiar. There’s none of the awkwardness I’d expect from eyes that were just transplanted."

Hyuga Kagami smiled. "That’s good."

This pair of Eternal Mangekyō Sharingan that had belonged to Uchiha Ryota had been developed and used by the Fire Release clone for a long time. Having been continuously nourished by the Fire Release clone’s chakra, the eyes had developed an extremely high compatibility with its chakra.

And Hyuga Kagami’s Fire Release clone had been created using cellular tissue extracted from Shisui.

As a result, Shisui’s chakra was extremely similar to the Fire Release clone’s chakra, so naturally, he was highly compatible with this pair of Eternal Mangekyō Sharingan as well.

After checking the instruments monitoring Shisui’s vital signs, Hyuga Kagami said, "The cellular activity in your body has increased slightly. It may be because of the Eternal Mangekyō Sharingan transplant. Try drawing on the ocular power and see if you can use it normally."

Shisui closed his eyes.

Then he suddenly opened them.

The originally dark pupils within his eye sockets had transformed into the Eternal Mangekyō Sharingan, its pattern formed from interlocking triangles and diamonds.

Hyuga Kagami nodded.

The first step of the surgery—the eye transplant—had been successfully completed.

Next came the second step: injecting the fusion solution.

The fusion solution was extremely unstable. Once prepared, it could only maintain its effectiveness for an hour and could not be stored for long periods. Therefore, after completing the eye transplant, Hyuga Kagami began preparing it on the spot.

Since all the necessary materials and equipment had already been prepared, coupled with Hyuga Kagami’s extraordinarily perceptive Tenseigan, preparing the fusion solution did not take much time.

In less than thirty minutes, Hyuga Kagami successfully prepared a container of highly active fusion solution.

Walking over to the operating table, Hyuga Kagami said, "Be careful. I’m going to inject the fusion solution now."

Shisui nodded lightly, his expression calm.

Hyuga Kagami poured the fusion solution into the infusion apparatus. Soon, the pale green solution flowed through the IV tube and entered Shisui’s body.

In an instant, the veins and chakra pathways throughout Shisui’s body began to swell, as though something were fermenting inside him. A thin layer of sweat also appeared across his forehead.

There was no doubt that Shisui was enduring excruciating pain at that moment.

He simply refused to make a sound.

At this point, Hyuga Kagami picked up the First Hokage cell tissue he had prepared for implantation from the instrument table and said, "The effects of the fusion solution are time-sensitive. I have to implant the First Hokage cells into you immediately. Are you ready?"

Shisui gritted his teeth and nodded.

"Don’t forget to use your ocular power. Willpower alone won’t be enough to resist the First Hokage cells’ erosion!"

After giving him one final warning, Hyuga Kagami officially began the First Hokage cell transplant.

In Hyuga Kagami’s view, whether it was Uchiha Madara, Obito, or Danzo, none of their transplants could be considered perfect.

That was because all of them bore obvious traces of transplantation.

For example, there was the First Hokage’s face on Uchiha Madara’s chest, Obito’s transplanted half-body, and Danzo’s arm that clearly did not belong to him.

A truly perfect transplant should occur at the genetic level.

Second best was the cellular level.

And only as a last resort should it be performed at the limb level.

Uchiha Madara and Obito’s transplants fell somewhere between the cellular level and the limb level. They could be considered imperfect cellular-level transplants.

Danzo’s transplant, on the other hand, was clearly a limb-level transplant.

The transplant surgery Hyuga Kagami was currently performing on Shisui was aimed at achieving a perfect cellular-level transplant.

Simply put, once the surgery was complete, none of Shisui’s physical features or appearance would undergo any changes. Every transformation within his body would be contained entirely at the cellular level.

In the entire shinobi world, there were probably only three people whose techniques had reached such a level:

Hyuga Kagami, Orochimaru, and Hiruko.

"Ah..."

After the First Hokage cells were implanted, even a shinobi like Shisui couldn’t suppress a cry of pain.

"Hold on!"

Hyuga Kagami did not hesitate or pause because of Shisui’s cry.

Now that the transplantation process had begun, there was no turning back. They could only grit their teeth and see it through to the very end.

And as more and more First Hokage cells were implanted, numerous fleshy sprouts began emerging from Shisui’s body, resembling tiny saplings on the verge of breaking through the soil...