Chapter Ten: In His Lonely Youth, Black Zetsu Encountered a Dazzlingly Brilliant Chess Piece

"It really is him..."

Black Zetsu felt a complex mix of emotions. It was a tangle of pleasure, unease, and inner conflict. Although Emiya Shiyuan's appearance in this era was an accident, and he had ultimately abandoned Black Zetsu in the ancient past, Black Zetsu still felt a sense of nostalgia for the time they had worked together.

This peculiar sensation... it was like encountering someone too brilliant to behold during the most wretched moment of one's life.

Whenever Black Zetsu thought of Emiya Shiyuan, it would inevitably recall their first meeting.

At that time... Emiya Shiyuan was in the middle of attempting to assassinate Indra.
At that time... Indra still possessed the Three-Tomoe Sharingan.
At that time... Black Zetsu had dismissed him as some insignificant nobody throwing his life away.

As it turned out... the battle that followed nearly scared Black Zetsu to death. It had never expected that this "nobody," having obtained the remains of the Divine Tree, would master Wood Release and natural energy, possess formidable taijutsu and swordsmanship, and even have a small slug by his side. He had completely overwhelmed the Three-Tomoe Indra, leaving him unable to even lift his head.

Because Black Zetsu had been secretly tracking Indra, its attempt to intervene caught Emiya Shiyuan's attention, causing him to abandon the assassination. Later, Black Zetsu could not escape, and thus, it came to know Emiya Shiyuan.

It learned of Emiya Shiyuan’s ambition: to annihilate the Shinobi Sect founded by the Sage of Six Paths.

As the Sage grew old and frail, the philosophy of the Shinobi Sect had gradually spread, and some disciples left to return to their homes. While some used chakra to benefit their lands, others were consumed by greed and began to exploit chakra for profit. Emiya Shiyuan was one of the victims. To steal a few bottles of fine wine, a certain Shinobi Sect disciple had used his chakra to slaughter an entire village; Emiya Shiyuan had only survived because he had left the village earlier.

Seeking revenge, Emiya Shiyuan prayed to the remnants of the Divine Tree and ultimately gained the power of Wood Release. The power of Wood Release was indeed strong, but attempting to challenge the Sage of Six Paths with it was nothing short of a pipe dream. Black Zetsu never believed this pawn would be of much use. It paid little attention to him, knowing only that he traveled the world saving lives and spreading the creed of the "medical ninja."

Back then... Black Zetsu had been riding high. Its first plan had succeeded; it had instigated a conflict between Indra and Asura, hoping Indra would seize Asura’s power and awaken the Rinnegan. But Indra had been soundly defeated by Asura. The first plan had failed quickly, and the once-triumphant Black Zetsu had been forced to sulk in the shadows.

During its time of despair, Emiya Shiyuan continued to save people everywhere, proclaiming that chakra was a power meant to relieve the world of suffering, not a weapon for Shinobi Sect disciples to inflict pain.

In that era, Emiya Shiyuan truly possessed a prestige that surpassed the Sage of Six Paths. People of that time had long worshipped the Divine Tree, and the Sage had destroyed that faith. In comparison, Emiya Shiyuan, who was constantly saving lives, was highly respected, especially since he worshipped the Divine Tree just as they did. He always had a small, snot-like slug hanging from his shoulder as he traveled, healing the sick, and even the Sage and his son Asura admired his convictions.

Emiya Shiyuan created the creed of the medical ninja. Enduring pain that others could not, he strove to save those who could not escape their own suffering. Such a virtuous belief... even the Sage of Six Paths, that hypocritical, self-righteous man, could not help but admire it.

Even Black Zetsu found that Emiya Shiyuan was, in truth, a kind and good man. Of course, adhering to the principle that villains also like good people, Black Zetsu found Emiya Shiyuan to be a useful "good man." During those lonely years after its plan failed, Black Zetsu acted like a kindred spirit, tirelessly whispering slanders about the Sage of Six Paths into Emiya Shiyuan’s ear. Together, they criticized the Shinobi Sect disciples who abused chakra.

In doing so, Black Zetsu revealed many secrets. For instance, that the Sage of Six Paths was the source of all chakra. This was not a secret in that era—one could learn as much by capturing any disciple—but it piqued Emiya Shiyuan’s curiosity. After the Sage died, Emiya Shiyuan wanted to dissect his remains to understand the origin of chakra, hoping to find a way to reclaim the chakra that was causing the world so much pain.

Black Zetsu knew it wasn't out of a desire for power. As a medical ninja, he needed to study human anatomy. Emiya Shiyuan was the first to dissect corpses, all to refine his medical skills. He had told Black Zetsu more than once that he wanted to break the prejudice against surgery. He intended to turn his own body into a specimen after death so that future generations could study it, and in the end, he had indeed done so.

Black Zetsu provided the location of the Sage’s corpse. Because the Sage’s power was heaven-shaking, Black Zetsu dared not approach it, fearing that even in death, the Sage might still possess the power to sense its presence. Emiya Shiyuan, however, had no such reservations. He stole the body with clinical efficiency. To study it, he traveled to a place rich in natural energy—a place called Shikkotsu Forest, filled with deadly acidic liquid. Though Emiya Shiyuan invited Black Zetsu to join him, it dared not enter the lethal forest.

When Emiya Shiyuan reappeared, he was accompanied by a massive slug; he had acquired a portion of the Sage’s power and successfully transplanted the Sage’s Rinnegan. Black Zetsu had never imagined that humanity could achieve such results through anatomical research!

That time... before Black Zetsu could even guide Emiya Shiyuan on how to collect chakra, he had taken the initiative! With one strike, he shattered the entire Shinobi Sect. He slaughtered countless disciples and turned the sect’s village into ruins. He was only a step away from destroying the organization the Sage had created.

That was the closest Black Zetsu had ever come to success. It was also the most satisfying revenge it had ever taken against the Sage—not just a physical destruction of the sect, but a spiritual evisceration.

Yet... Emiya Shiyuan lost to Asura.

He had encountered Asura before. While secretly collecting the remains of the Divine Tree, he had met Asura helping villagers dig a well and had deemed him a good man. In the end, swayed by Asura’s earnest persuasion, Emiya Shiyuan chose to believe in his promise—the promise that Asura would lead everyone to possess the power to save the suffering world.

This man... he had decided to entrust his dream to Asura.

To atone for his actions, Emiya Shiyuan used the Rinne Tensei Jutsu hidden within the Rinnegan to bridge the gap between life and death, resurrecting those who had fallen in battle. Because of the immense power of the Six Paths, he did not die immediately after performing the technique; he returned to Shikkotsu Forest to prepare for his end.

When he finally appeared again, there remained only a crystal coffin containing half his body, which the slug entrusted to Asura.

What a naive man... to actually believe in Asura’s promise.

Yet, Emiya Shiyuan’s success revealed another possibility to Black Zetsu. Throughout the long, millennium-spanning years that followed, Black Zetsu spent its time inciting conflict between the descendants of Indra and Asura, while simultaneously promoting the greatness of the medical ninja, hoping someone would master human experimentation just as Emiya Shiyuan had.

Come to think of it... this was a source of constant confusion for Black Zetsu. It was a warmonger orchestrating slaughter, yet simultaneously a holy messenger spreading the gospel of healing. If Emiya Shiyuan’s story continued to circulate in this era while the Sage’s story became mere legend, it was undoubtedly due to Black Zetsu’s own efforts.

Unfortunately... whether through its own schemes or Emiya Shiyuan’s methods, Black Zetsu never again saw a glimmer of success.

And that was precisely why it missed Emiya Shiyuan so much. He was the one instance, out of countless plans executed, that had come infinitely close to succeeding.

What a pity... if only Emiya Shiyuan hadn't believed in Asura back then.

"Hehehehe..."

A mocking smile played on Black Zetsu’s face. It imagined the look on Emiya Shiyuan’s face, should they meet again—the regret and shame he would surely feel for his past betrayal.

"Now that you see these ninjas locked in endless strife, do you regret the foolish words you believed back then?"