"It really is him…"
Black Zetsu felt conflicted.
A strange blend of joy and unease churned within him.
Though Emiya Shihara's appearance in this era was a complete anomaly—and though he ultimately betrayed Black Zetsu in ancient times—Zetsu couldn't help but miss the days they had once shared as allies.
It was a strange feeling…
Like crossing paths with someone too breathtaking during the bleakest chapter of your life.
Every time Black Zetsu recalled Emiya Shihara, his thoughts would drift back to their first encounter.
Back then…
Emiya Shihara was attempting to assassinate Indra.
At the time…
Indra still wielded only the Three Tomoe Sharingan.
At the time…
Black Zetsu had assumed he was just another reckless nobody courting death.
But then…
That battle had nearly scared Zetsu to death.
He hadn't anticipated that this so-called "nobody" had acquired remnants of the God Tree, mastered Wood Release and natural energy, possessed terrifying taijutsu and swordsmanship, and even had a tiny slug companion at his side—overwhelming Indra so thoroughly that the Uchiha prodigy could barely lift his head.
Because Black Zetsu had been secretly tailing Indra, his attempt to assist inadvertently caught Shihara's attention and interrupted the assassination attempt.
And from that moment…
Zetsu never escaped.
That was how he came to know Emiya Shihara.
He came to understand Shihara's ideals—his desire to destroy the shinobi sect founded by the Sage of Six Paths.
As the Sage aged and weakened, his teachings spread far and wide. Some of his disciples returned home, bringing chakra with them.
Some used chakra to benefit their people. Others became corrupted by greed and began wielding chakra for personal gain.
Emiya Shihara was a victim of such corruption.
One shinobi, coveting a few bottles of fine liquor, used chakra to massacre an entire village. Only Shihara survived—by sheer luck, having left the village just prior.
Driven by vengeance, Shihara prayed to the remnants of the God Tree and was granted the power of Wood Release.
Wood Release was strong…
But to challenge the Sage of Six Paths with that alone was sheer folly.
Black Zetsu never truly believed this "pawn" could amount to anything significant.
He barely kept track of him, only aware that Shihara traveled across the land healing the wounded and preaching a new belief—that chakra was meant to ease suffering, not to become a weapon of oppression.
At the time…
Black Zetsu was riding high on success.
For the first time, one of his schemes had borne fruit: he had successfully incited Indra to challenge Asura, hoping the battle would push Indra into awakening the Rinnegan.
Instead, Indra suffered a crushing defeat.
Zetsu's grand plan crumbled almost instantly.
Humbled, he retreated into the shadows once more.
While he brooded in despair, Shihara was still out there, healing the sick and preaching that chakra should be used to ease pain, not inflict it.
In that era…
Emiya Shihara came to command a reverence that even surpassed the Sage himself.
For in those days, the people still worshipped the God Tree, while the Sage had destroyed what they held sacred.
By comparison…
A man who never ceased healing, who shared their faith in the God Tree, was far more deserving of their admiration.
On his shoulder always sat a snotty little slug, accompanying him on his journeys, curing the world's ills. Even the Sage and his son Asura admired Shihara's unwavering belief.
He was the origin of the "medical ninja" creed.
He bore pain the world could not endure, yet strove to rescue those consumed by it.
That kind of compassion…
Even a so-called "paragon" like the Sage of Six Paths had no choice but to respect it.
Even Black Zetsu…
Came to acknowledge that Shihara was truly a good man.
Of course…
As every villain secretly loves the good man they can manipulate—
Black Zetsu adored Shihara.
In those years of despair following his failed scheme, it was as if he had found a kindred spirit. He would whisper venom into Shihara's ear, slandering the Sage and his disciples who abused chakra to spread destruction.
And in doing so…
He revealed many secrets.
For instance, that the Sage was the true source of chakra.
That knowledge was not exactly hidden—capture any shinobi disciple, and you could coax it from them. But to Shihara, it ignited a deep curiosity.
After the Sage's death, Shihara wanted to dissect his body. He sought the origin of chakra, hoping to find a way to retrieve it from those who used it to harm.
Black Zetsu knew—he wasn't chasing power.
As a medical ninja, he needed to study human anatomy.
Shihara became the first to perform human dissection—not for dark arts, but to refine his medical skills.
He had told Zetsu many times: he hoped to break the world's prejudice against surgery. He intended to offer his own corpse as an anatomical specimen after death, so that future generations could learn from it.
And he would indeed fulfill that promise.
It was Black Zetsu who had given him the Sage's burial site.
Though Zetsu never dared approach—fearing the Sage's power might persist beyond death, and that even his corpse could perceive him.
But Shihara felt no fear.
He brazenly stole the Sage's body.
Taking it to a place rich in natural energy, Shihara secluded himself for years of research.
That place was called Shikkotsu Forest.
A forest filled with deadly acid.
Though he invited Black Zetsu to join him, Zetsu dared not step foot in that lethal swamp.
When Shihara reappeared in the world, he had a colossal slug at his side, had inherited a portion of the Sage's power, and had successfully transplanted the Rinnegan.
Black Zetsu had never imagined—
That human anatomical study could yield such power.
That time…
Before Zetsu could even guide him in harvesting chakra—
Shihara acted first.
He annihilated the entire shinobi sect in a single strike.
He slaughtered countless disciples and reduced their village to ashes—coming within an inch of wiping out the Sage's legacy forever.
It was the closest Zetsu had ever come to victory.
The sweetest revenge he'd ever tasted against the Sage of Six Paths.
Not just physical destruction, but a psychological blow—shattering the very ideals upon which the shinobi world was built.
But in the end…
Shihara lost to Asura.
Because he had once encountered Asura.
While collecting God Tree remnants in a village ravaged by their power, he had met a kind-hearted young man helping villagers dig wells.
He believed Asura was a good man.
In the end, swayed by Asura's heartfelt pleas, Shihara entrusted him with his dream.
He chose to believe in Asura's promise—that they could build a better world together, one that healed the suffering of mankind.
This man…
Entrusted his life's dream to Asura.
As atonement, Shihara used the Rinnegan's Samsara of Heavenly Life Technique to revive all those who had perished in battle.
Though the power was immense, Shihara did not die immediately. He returned to Shikkotsu Forest to prepare for his final rest.
When he appeared again, only half of his body remained—entombed in a crystal coffin, entrusted to Asura by his loyal slug.
What a naïve man…
To have truly believed in Asura's empty promises…
And yet, through Shihara's success, Black Zetsu saw a glimmer of new possibility.
Through the endless centuries, he continued to stoke the fires of conflict between Indra's and Asura's descendants—and quietly spread the gospel of medical ninjutsu.
Hoping someone would, one day, walk the path Shihara once walked.
And perhaps that was what left him in such turmoil.
A warmonger who manufactured wars…
Also doubling as a saint preaching salvation.
It was thanks to Black Zetsu's efforts that Shihara's legend endured—while the Sage of Six Paths faded into myth.
A shame, really…
For all his cunning and for all of Shihara's brilliance, no one ever again came so close to success.
And it was because of that…
That Black Zetsu missed him all the more.
Emiya Shihara—was the closest thing to victory he had ever known in all his countless schemes.
How regrettable…
If only he hadn't trusted Asura.
"Heh… heh heh…"
A mocking grin spread across Black Zetsu's face.
He imagined the look of remorse and shame on Shihara's face if they were ever to meet again—if the man finally saw what had become of the world.
"Now that you've seen the endless wars of the shinobi… do you regret believing Asura's foolish promises?"