Chapter 4: The Other Pair of Mangekyō
Though Nan was initially surprised by this phenomenon, a bit of reflection quickly made it all seem reasonable.
After Sasuke transplanted Itachi's Mangekyō, he didn't gain access to Itachi's signature jutsu, Tsukuyomi. He could still only use his own techniques—Amaterasu and Blaze Release: Kagutsuchi.
This was quite different from Kakashi and Danzo, who could directly use the jutsu of the Mangekyō they had received from others.
That's because the Eternal Mangekyō, after awakening, uses the chakra and ocular power of the user—not the abilities of the transplanted eye. The original abilities of the transplanted Mangekyō are typically discarded during the fusion process.
Why? Perhaps it's because a single pair of eyes can't contain four distinct ocular abilities, so two must be sacrificed. Sasuke seemingly retained his own, and abandoned Itachi's.
Or more likely, the transplanted eye's abilities can never truly be harmonized with the user's chakra. In that case, the new eye serves merely as a catalyst to evolve the user's own ocular power, not as a carrier of usable techniques. The old abilities are meant to be discarded.
Whatever the reason, Sasuke only ever had one pair of Mangekyō to begin with.
But Nan was different—after absorbing Han, he now possessed two complete pairs.
What's more, the Mangekyō he absorbed from Han was fully compatible with his own. Both could coexist within a single pair of eyes, something entirely unprecedented in shinobi history.
This miracle could only be attributed to the mystical nature of Yin-Yang Release: Formless Reincarnation.
Even better—both of Nan's Mangekyō were freshly awakened. Their ocular power remained at full strength, and neither was weaker than the other. There was no "dominant" or "subordinate" eye.
That's why it made perfect sense that even after awakening the Eternal Mangekyō Sharingan, Nan was still able to retain and access the abilities from both Mangekyō. His eyes had already been fundamentally transformed by Formless Reincarnation—they were no longer normal eyes by any means.
Now that he fully understood this, Nan no longer found his condition strange.
"I just didn't expect my ocular powers to be even more miraculous than I imagined! I can even reshape the vessel of my own existence!" Nan couldn't help but marvel aloud.
Originally, he had worried that his unique Mangekyō ability might not be usable under normal conditions, which would've drastically reduced his combat capabilities.
A Mangekyō without a reliable, combat-ready ability was practically crippled. Sure, Susanoo was powerful, but it had its limitations. Without a more flexible jutsu, his ability to adapt in battle would be sorely lacking.
But now, that concern had completely vanished.
Nan was thrilled to discover that the ocular abilities he had acquired from Han hadn't been lost during the fusion—they were still there, still usable.
And those abilities were exactly the kind of techniques he needed: battle-ready ocular ninjutsu that could be activated at will.
He had to admit, there really were similarities between blood brothers. Han's ocular powers, just like Nan's own, were Yin-Yang-based Mangekyō techniques.
In fact, both of Han's eyes used the same jutsu name as Nan's—a remarkable coincidence, or perhaps fate.
Since the ability could be used normally, Nan didn't hesitate any longer. It was time to test it out.
Thanks to having absorbed Han's chakra, he now had the necessary energy to activate the jutsu immediately.
He stood firm, feet shoulder-width apart. His eyes narrowed. His hands formed a seal. He centered his breathing. Then he shouted:
"Yin-Yang Release: Phantom Body Technique!"
Don't ask why he went through all that drama. During the fight with Han, it was a life-or-death situation—there was no time for flair. But now that things had settled down, he felt it was only right to give his first Mangekyō jutsu a proper ritual.
After all, he'd spent so many years watching Naruto—how could he not?
As expected, the jutsu activated successfully.
From Nan's perspective, two translucent humanoid figures—one black and one white—materialized before his eyes. They were the phantom bodies conjured by the Phantom Body Technique.
What Nan hadn't expected was just how much chakra it would take to summon the phantom bodies. The cost was far greater than he'd imagined.
Even with the extra chakra he had absorbed from Han, Nan's total reserves were nearly at the average jōnin level—and yet, it still wasn't quite enough.
If not for the fact that his Mangekyō was continuously feeding chakra back into his body, he would've already collapsed from exhaustion.
"Hah... Looks like this technique can't be used mid-battle. I'll have to remember to prepare the phantom bodies in advance," Nan gasped, breathing heavily, but still making a mental note for the future.
Each phantom body was a chakra construct forged from Yin-Yang Release—similar in nature to the Tailed Beasts.
Unlike the Tailed Beasts, though, these phantoms didn't possess the same overwhelming chakra volume. However, they had an extraordinary advantage in stealth: they couldn't be seen with the naked eye and were undetectable unless the observer possessed a dojutsu.
Each phantom body had its own unique ability. The black phantom was summoned by Nan's left eye and was aligned with Yin Release.
This Yin phantom existed in a semi-spiritual form and specialized in mental and spiritual attacks.
It could use Yin-based chakra to cast genjutsu, execute illusion techniques, and even possess enemies directly to control their bodies.
Through the Yin phantom, Nan gained access to extremely advanced sensory techniques. The phantom's speed was astonishing—it could instantly move within its sensing range, a trait strikingly similar to Kato Dan's Spirit Transformation Technique.
With this in mind, Nan quickly scanned his surroundings through the phantom's senses. Ever since the fight with Han, he'd been worried someone might've witnessed what happened.
Fortunately, the Yin phantom sensed no foreign chakra nearby, allowing Nan to finally relax.
Had anyone been lurking, Nan would have had no choice but to eliminate them—no matter who it was.
The white phantom, on the other hand, came from his right eye and was aligned with Yang Release. This one was more physical and capable of dealing real, tangible damage.
The Yang phantom could utilize Yang Release ninjutsu and taijutsu to inflict physical harm. It also boasted an incredible healing factor, greatly enhancing the effectiveness of medical ninjutsu.
The part that pleased Nan the most, however, was a special ability called "Substitution."
This ability allowed Nan to transfer any injury he sustained directly onto the phantom. As long as he wasn't outright killed, he could fully recover from even the most devastating wounds in an instant—an ability so powerful it bordered on broken.
And because the phantoms were similar to Tailed Beasts in nature, they couldn't be truly destroyed. If one suffered too much damage, it would automatically dissolve and return to Nan's Mangekyō.
If Nan recalled a phantom voluntarily, he could summon it again without expending additional chakra. But if a phantom was forcibly dispersed, summoning it again would cost the same as the first time.
Once manifested, however, the phantoms could refine their own chakra independently. They wouldn't drain Nan's reserves at all.
In fact, Nan could even dissolve a phantom on purpose to absorb its chakra and replenish his own.
This ability greatly enhanced Nan's stamina and endurance, giving him far more flexibility in both combat and strategy.
Moreover, Nan could sense that his eyes didn't stop at just two phantom bodies—he had six in total.
This, he believed, was because he possessed the Eternal Mangekyō. If it were a regular Mangekyō, two might have been the limit.
The abilities he'd acquired were incredibly comprehensive—enough to instantly elevate a boy who hadn't even graduated from the Academy into a well-rounded ninja.
If not for his lack of real combat experience, Nan might already be approaching—or even surpassing—Kage level in raw power.
"If someone just looked at my appearance, they'd never imagine that a six-year-old child already possesses the power to rival a Kage," Nan murmured to himself.
It was hard to believe: he had only just arrived in the shinobi world, yet already had the strength to stand near the top.
But then he remembered all the monsters who would eventually appear in this world—and immediately crushed any budding arrogance.
From Uchiha Nan's memories, he knew this was currently Year 46 of the Hidden Leaf Village. The entire Naruto storyline would begin unfolding within the next two years.
And as a child who hadn't even left the Academy, Nan's current influence on the future would be negligible.
He knew better than to intervene too early and risk throwing the timeline off course. Doing so could destroy the strategic advantage of his foreknowledge.
Besides, Madara was still alive somewhere. And Black Zetsu was no doubt hiding in the shadows. If Nan revealed his abilities too soon, he would surely attract their attention—and that would spell disaster.
Whether it was the masked man Obito who would soon appear, the eventual return of Madara and Kaguya, or the arrival of the Ōtsutsuki clan from beyond the stars—Nan had no chance against any of them as he was now.
So he made a silent vow to himself:
"I have to use this time—before the main storyline begins—to train, to sharpen my abilities, and to grow stronger. Only then will I be able to seize control of my destiny in the chaotic storm that is the shinobi world."
He had come to this world—no way back in sight. So he might as well accept it.
This would be the start of a new life.
And the first step was establishing a foothold in the shinobi world.
Drawing on Uchiha Nan's memories, he quickly made his way out of the Forest of Death and returned to the Uchiha clan's compound—his new home.