Shinigami in the Ninja World (Re-upload)

Beneath Sōkyoku Hill

Secret Base

Kisuke Urahara was undoubtedly a remarkable genius. The entrance to the underground base was meticulously concealed. Without Yoruichi leading the way, even Sasuke's Sharingan might have been fooled by the intricate layers of false information laid out to mislead intruders. While the deception alone wouldn't cause significant harm, the triggered Kidō traps that followed would be anything but pleasant.

Not to mention...

Yoruichi had repeatedly warned him to tread carefully. Triggering even one of these traps could spell trouble, but if two traps were activated simultaneously, an even more devastating Kidō mechanism would activate, collapsing the entire underground structure.

For Sasuke and Yoruichi, escaping might not have been a challenge. However, this time, the stakes were different. Several captains, still unconscious from the Hollowfication process, lay nearby. A collapse would almost certainly spell disaster.

"Kisuke…" Yoruichi muttered, her sharp gaze sweeping the dimly lit chamber.

"Oh, Sasuke-kun has arrived," Kisuke greeted, his tone as lighthearted as ever. Yet, his usual cheer was undercut by the exhaustion etched into his features.

Sasuke glanced at him briefly, remaining silent.

Their relationship was far from close. If Kisuke wanted to put up a façade of strength, Sasuke saw no reason to challenge it.

After all, he was now the acting captain of the 2nd Division.

And Kisuke Urahara was technically his mission target.

"I must apologize," Kisuke sighed after a moment, his tone softer. "Because of me, Yoruichi's plans had to be rushed. And it forced you, Sasuke-kun, into the spotlight before you were ready."

He hesitated. "Yoruichi and I…"

In Yoruichi's original plan, Sasuke was supposed to take over the 2nd Division only after reaching captain-level strength or mastering Bankai. By then, he would have the unwavering support of two experienced captains.

Additionally, captains from commoner backgrounds, or those like Shunsui Kyōraku—neutral in their stance between nobles and commoners—would likely remain silent, ensuring Sasuke's path forward was smooth.

But now...

The two individuals who should have been Sasuke's strongest allies were about to "disappear." Regardless of whether they survived, they would no longer be able to support him.

"What's the point of apologizing?" Sasuke interrupted curtly. "Are you planning to stay here?"

Kisuke froze.

"If not, then stop wasting time with apologies and focus on fixing the problem," Sasuke said flatly, shaking his head.

He had learned through painful experience that 'words were powerless.'

Words couldn't undo the annihilation of the Uchiha clan.

Words couldn't kill Itachi Uchiha.

And words couldn't make him stronger.

Kisuke fell silent, and even Yoruichi seemed momentarily at a loss.

Yoruichi reached for something nearby, tilting her head as she spoke. "Kisuke, there's no point in apologizing anymore."

"Like Sasuke said, apologies won't solve anything. What matters now is minimizing the trouble he'll face in the future."

Sasuke's attention shifted.

In Yoruichi's hand was a pale, humanoid puppet. It appeared unremarkable at first glance, save for its peculiar design. Within, a faint trace of spiritual energy lingered.

"How does it work?" Sasuke asked, his tone direct.

"Touch it and infuse it with your spiritual energy," Kisuke explained, stepping forward despite his weariness. "Your Zanpakutō will manifest physically."

"Then, you'll need to conquer it in your own way."

Sasuke raised his hand, gesturing for Kisuke to continue.

"However," Kisuke added, "you should remember that conquering a Zanpakutō isn't always about defeating it in combat."

"For example, my 'Benihime' and I had a contest of intellect. Yoruichi played a game with hers."

"You have three days. In that time, you must discover the method that works for you and conquer your Zanpakutō."

"Yoruichi and I will assist however we can."

Sasuke nodded and extended his hand toward the puppet.

The moment his fingertips made contact, the spiritual energy within the puppet surged, bursting forth in a radiant light. The heat-filled brilliance rapidly expanded, consuming Sasuke's energy and spreading like a web throughout the puppet.

Inside, the light began to take form, growing like an umbrella.

The aura shifted, resonating with Sasuke's Zanpakutō.

The puppet changed, taking on a lifelike presence. Its once featureless, humanoid shape transformed into a tall man with long black hair and sharp, arched eyebrows.

In his eyes, three tomoe circled—a 'Three-Tomoe Sharingan.'

The man's fierce, domineering aura seemed to devour everything around him. Despite his stoic expression, hostility seeped from his every movement.

Yet to Sasuke, this man felt strangely familiar.

A wielder of the Sharingan...

Though this was merely the manifested spirit of his Zanpakutō, the Sharingan, coupled with its independent will, made Sasuke regard him as if he were a member of the Uchiha clan.

In this world, he might be Sasuke's only family.

"That man," Sasuke thought bitterly, "is no kin of mine."

What kind of relative would slaughter their entire clan?

"Sharingan." The spirit's gaze moved, scanning Kisuke and Yoruichi before settling on Sasuke. "A pair of eyes like these... Are you my descendant?"

Sasuke froze.

'Descendant?'

What?

Since when did Zanpakutō spirits claim to be ancestors?

He turned to look at Kisuke in confusion.

Nothing in the Shin'ō Academy textbooks or Kisuke's private teachings had ever mentioned such a phenomenon.

A Zanpakutō spirit refusing to acknowledge itself as a weapon and instead claiming to be an ancestor?

What was going on?

This... didn't feel right.

Role-playing?

Or was his Zanpakutō so unruly that it even sought to assert dominance over its wielder?

Kisuke shook his head subtly, signaling Sasuke to stay calm and proceed with the usual steps to conquer his Zanpakutō.

The silent exchange didn't escape the black-haired man's sharp gaze.

He tilted his head slightly, his sharp eyes narrowing. Spiritual pressure rippled from him like waves, as if he were rifling through his own memories or investigating something buried within himself.

"So that's how it is."

When Sasuke and Urahara finished their silent exchange, the man seemed to have found what he was looking for. He gave a slight nod.

"Zanpakuto, materialization, Shikai…"

He paused, his tone growing stern. "You desire power, don't you?"

"Of course," Sasuke replied without hesitation.

"Seeking my acknowledgment to gain the so-called 'Shikai' power," Indra smirked. "It won't be an easy task."

"Even with those eyes—those same eyes as mine…"

"How far have you developed the potential of those 'Sage Eyes'?"

Sasuke blinked in confusion.

'Sage Eyes?'

'Is that another name for the Sharingan?'

Indra raised his hands, pressing them together in a gesture Sasuke immediately recognized. It was a hand seal—a familiar one, frequently used in sparring sessions back in the ninja academy: 'the Seal of Reconciliation.'

"Come then. Use everything you have," Indra said softly. "If you can defeat me, I'll acknowledge you."

Sasuke drew his blade.

'Defeat him...'

Kisuke Urahara had just explained that defeating one's Zanpakuto wasn't always necessary for acknowledgment. But in this case, it seemed to be his only option.

'Fine. This was what Sasuke excelled at.'

One figure flashed forward with a 'Shunpo,' while the other surged with a 'Body Flicker Technique.'

Indra's combat style took Kisuke and Yoruichi by surprise.

It wasn't anything they were familiar with—neither typical 'Kidō' nor the usual techniques of a Shinigami. Instead, it was a unique, formidable style, involving substitutions, clones, and intricate hand seals.

Sasuke, however, adapted almost instantly.

There was no adjustment period; his familiarity with such techniques allowed him to immediately understand and counter Indra's methods.

"This is the worst-case scenario," Yoruichi muttered, her brows furrowing.

Kisuke remained silent, his expression grim.

It was indeed the worst-case scenario—defeating the materialized Zanpakuto to earn its acknowledgment.

This wasn't an easy feat.

Materialized Zanpakuto often possessed 'Bankai,' meaning they had captain-level combat capabilities. Even if their spiritual pressure didn't quite meet the mark, their raw power and techniques were undeniable.

For someone like Sasuke, who hadn't yet attained captain-level strength, defeating such an opponent demanded immense skill.

This reminded Yoruichi and Kisuke of an ancient legend.

Long before 'Bankai' existed, even before Zanpakuto were created, Shinigami wielded a power called 'Shin'uchi (True Strike).'

According to the legend, 'Shin'uchi' was a precursor to 'Bankai.' As one of the heads of the Five Noble Families, Yoruichi knew the truth: 'Shin'uchi' was less a weapon and more a standard.

It was the same requirement Indra now set for Sasuke—to achieve captain-level strength without relying on a Zanpakuto.

Currently, only a few elderly figures in Seireitei could claim such prowess. Most captains relied heavily on their Zanpakuto.

"Believe in Sasuke," Kisuke finally said softly, lowering his gaze. "He'll make it."

"What if he doesn't?" Yoruichi hesitated. "Even if my plans fail, I can't let Sasuke pay a greater price for it."

Kisuke rested his hand on the hilt of his Zanpakuto, casting a glance toward the depths of the base. "I've got this."

"The 'Tenshintai' is risky, but it's not without solutions."

"And—"

"There's more than one way."

Kisuke's confidence stemmed from two items in his possession.

One was his Zanpakuto, 'Benihime,' whose 'Bankai' could modify anything it touched, living or inanimate, including Zanpakuto.

The other was the 'Hōgyoku.'

Though dangerous and incomprehensibly powerful, the 'Hōgyoku' had the ability to grant its wielder's desires. No matter how improbable or bizarre the wish, even restoring a Shinigami's ability to achieve 'Bankai' was within its capabilities.

"Go," Yoruichi waved him off. "Compared to Sasuke, Hirako and the others need you more."

"I'll call for you if anything changes here."

Kisuke nodded and disappeared deeper into the base. He was more worried about the Hollowfied captains, including his own lieutenant, who had never been particularly fond of him.

Yoruichi turned her attention back to the battle but soon grew bored.

It dragged on.

Indra was immensely powerful. His experience, combat instincts, and mastery of techniques far surpassed Sasuke's.

Moreover...

Their fighting styles were dangerous.

Both tested and pressured each other before unleashing their strongest moves. The stronger won, the weaker lost.

One or two bouts were exciting to watch, but as the patterns repeated, Yoruichi found herself predicting their moves before they happened. She could foresee the entire sequence after seeing the initial hand signs.

Yet, she couldn't deny the effectiveness of such methods.

For members of the 'Stealth Force,' this combat style was tailor-made.

As night fell—

"Take a break," Indra said after another round, gesturing dismissively.

Sasuke gritted his teeth. "No."

"I can keep going."

Though his body showed signs of strain, Sasuke ignored them. The relentless high-intensity battles were undoubtedly taxing.

But...

He could endure it.

In the past, whenever he returned to the ninja world from the Soul Society, his body felt rejuvenated, no matter how exhausted he had been.

It didn't matter how grueling the tasks or training were—he always returned to Konoha feeling refreshed.

At most, he'd rest when back in Konoha.

Right now, 'Bankai' was the priority.

"This isn't a request," Indra countered, sitting cross-legged in a corner. "No matter what you want to achieve, your body is your most important asset."

"Don't you find those earlier battles boring?"

"Neither your tactics nor your body movements brought me any excitement," Indra said flatly, his face expressionless and voice calm.

Sasuke gritted his teeth, his fists clenched tightly.

"Just listen to your sword," Yoruichi interjected, walking over and slinging an arm around Sasuke's neck. "You've only gone through a third of the time. There are still two days left."

"You've got plenty of time."

"This base has something extraordinary, something that only the Zero Division gets to enjoy. Kisuke, being Kisuke, managed to recreate it."

"A hot spring. Dip into it, and no matter what injuries you've sustained, you'll heal and recover completely."

Sasuke shrugged off Yoruichi's hand. "Then let's get started already."

...

Three hours later

A rejuvenated Sasuke once again challenged Indra.

In those three hours, not only had his physical strength returned, but his mental sharpness had also been fully restored.

He realized he had been too entrenched in his "ninja" combat style. Though he still didn't completely understand who Indra truly was—likely an ancient Uchiha ancestor—it was clear that his identity was far from ordinary.

The expertise, the ancient ninja combat techniques, and the mastery of a variety of jutsu were not qualities that could be attributed to a Zanpakuto born solely from the Soul Society.

If Indra was indeed a seasoned, ancient ninja, then relying solely on "ninja" methods was a trap. Trying to defeat him in his area of expertise was both foolish and inefficient.

Shaking off these constraints, Sasuke began integrating more Shinigami elements into his combat style—'Hadō', 'Bakudō', and, of course, the Sharingan, which remained at the core of his technique.

This shift in approach, developed over a mere three hours, caught Indra's attention.

His eyes gleamed with intrigue.

...

The First Day

The first day passed in relentless battle.

The Second Day

The second day unfolded in much the same way.

The Third Day

On the third day, beneath a sky heavy with clouds, Kisuke Urahara emerged from the depths of the base and approached Yoruichi.

"Hirako and the others have woken up," he informed her.

"It's resolved?" Yoruichi's eyes lit up with hope.

If those captains and lieutenants were fine, everything else would fall into place.

She could resign and take responsibility for her crimes against the Central 46, while Sasuke could remain as captain. Kisuke could clear his name, and Hirako Shinji and the others would owe her a favor, ensuring their support for Sasuke.

With that, more than half of the Gotei 13 would be on Sasuke's side.

Kisuke offered a bitter smile and shook his head. "No. Even with the Hōgyoku, I can't entirely remove the effects of something on this level."

"I've only suppressed the Hollow powers encroaching on their Shinigami essence. I can't completely purge it."

Yoruichi sighed deeply, the weight of the situation settling on her shoulders. "I see..."

"Then we really have no choice but to leave the Soul Society."

Not wanting to linger on the negative, Kisuke changed the subject. "How's Sasuke doing?"

"Not great," Yoruichi admitted, her face darkening further. "He's able to hold out longer now, but he still can't match that guy."

Despite her usual disdain for notions of fate, the string of bad luck had her questioning whether it was, in fact, destiny.

"That guy is incredibly strong," Yoruichi said, glancing at Kisuke. "Even if I don't suppress him with raw spiritual pressure, relying solely on combat experience and technique, I'm no match for him."

She acknowledged this without hesitation.

"To that extent?" Kisuke was stunned.

Typically, the gap in ability between a Shinigami and their Zanpakuto wasn't that large. A materialized Zanpakuto might be stronger, but not to this degree.

"Then how about Yoruichi steps in first?" Kisuke suggested, his fingers lightly brushing his Zanpakuto's hilt. "Once he's under control, I'll take over."

"Be careful. Benihime is dangerous."

Yoruichi nodded in agreement.

…

The Final Battle

Indra stood tall, gazing down at Sasuke, who lay defeated at his feet.

A faint smile tugged at his lips. "Sasuke Uchiha, my descendant, you truly are remarkable."

Sasuke sneered in response, frustration and disbelief swirling within him.

'How absurd…'

To be praised by the very person who had just beaten him.

Indra raised his hand, forming a seal. Before activating the technique, he glanced briefly at Yoruichi and Kisuke Urahara.

"What you're worried about won't happen," he said calmly. "Let me and Sasuke share some private words."

The moment he finished speaking, the technique unfolded.

Centered on his fingertips, a barrier expanded in all directions. Translucent and glowing with a faint purple light, it encased them both, cutting off any external interference.

"Who exactly are you?" Sasuke demanded as soon as the barrier was complete.

Indra spoke softly. "Didn't I already tell you? I am your ancestor."

"There's no record of an ancestor named Indra in the Uchiha clan," Sasuke countered, shaking his head. He prided himself on knowing the clan's history, especially its most notable figures.

"The Uchiha clan?" Indra chuckled. "I existed long before the Uchiha clan's history even began.

"My father was Hagoromo Ōtsutsuki—what you know as the Sage of Six Paths."

Sasuke froze, his eyes widening slightly.

'The Sage of Six Paths?'

The origin of all ninja. The first wielder of chakra.

"Let me think about how to explain this." Indra tilted his head, his tone casual despite the gravity of his words. "After my father passed, I had a… conflict with my brother, Asura.

"Our battles were relentless and bitter—a cycle of endless strife.

"Even after we died, our grudges didn't dissipate. Our chakra continued to reincarnate, attaching itself to our descendants."

Sasuke narrowed his eyes, tilting his head slightly in thought.

'Reincarnated chakra…'

That was something he'd never encountered before.

"And this world," Indra continued, "is truly remarkable. The existence of souls, Zanpakuto, and the reflection of the heart within them awakened my chakra.

"Asura and I are different. His chakra carries his consciousness, allowing him to act through his reincarnations. But I… I chose to bide my time, waiting for a day like this."

He paused briefly before asking, "Sasuke, can you return to the ninja world?"

Sasuke nodded. "Yes, I can."

"It seems the heavens have arranged this," Indra said, leaning forward slightly. "All I ask is that you agree to one condition. If you do, I will accept you as my wielder."

"What condition?" Sasuke asked.

"Find Asura's reincarnation in your generation," Indra said firmly, his tone heavy with conviction. "And when his Asura energy awakens, defeat him."

"How will I find him?" Sasuke inquired.

"You won't need to search." Indra shook his head. "Our chakras are intertwined. He will inevitably cross your path."

Sasuke nodded. "That won't be a problem."

Indra smiled faintly. He didn't doubt Sasuke's resolve. Through his chakra, Indra could glimpse the memories of his past reincarnations.

No matter who he had been, or what he had pursued, his fate had always been to battle Asura's reincarnation.

"That's not all," Indra said softly. "The Sharingan is a reflection of the heart, just like a Zanpakuto is. But do you know that the Sharingan can evolve even further?"

Sasuke nodded, his expression darkening as he recalled a certain man. Gritting his teeth, he spat, "Of course. The Mangekyō Sharingan."

Indra continued, "For your clan, this evolution has always been a step backward.

"My father, the Sage of Six Paths, had the most complete version of the Sage Eyes, known as the Rinnegan.

"I inherited those eyes, though they were already inferior to my father's.

"And you—those who carry my bloodline—have inherited eyes that are weaker still."

He paused. "From my memories, I've seen that the Sharingan can evolve further: first into the Mangekyō Sharingan, then the Eternal Mangekyō Sharingan, and finally into the Rinnegan."

Sasuke interrupted, "Eternal Mangekyō? What's that?"

He knew of the Rinnegan, a legendary power tied to the Sage of Six Paths.

"It's a cruel process," Indra explained. "Two siblings must awaken the Mangekyō Sharingan. One must then transplant the other's eyes into their own to achieve the Eternal Mangekyō Sharingan.

"The regular Mangekyō, though powerful, comes with a cost—progressive blindness.

"Only by evolving it into the Eternal Mangekyō can this drawback be eliminated."

Sasuke's eyes widened, his fists clenching as his body trembled.

'So that was it...'

It explained everything.

It explained why 'that man', after slaughtering the entire clan, had spared him.

He didn't do it out of kindness.

He had kept Sasuke alive, nurtured his hatred, knowing Sasuke would seek vengeance.

That hatred would push Sasuke to awaken his Mangekyō Sharingan.

And when the time came…

'That man would take Sasuke's eyes to awaken the Eternal Mangekyō for himself.'

Indra observed Sasuke's reaction but refrained from questioning him. He could sense the boy's deep-seated hatred, but it was none of his concern.

"I am already dead," Indra said quietly, exhaling softly. "Even if I can communicate with you now, it's only because of the unique properties of my chakra.

"The dead cannot evolve further.

"Which is why I believe…"

"That your so-called Bankai lies beyond your Sage Eyes."

He extended his hand, raising an eyebrow to signal Sasuke to take it.

Sasuke clasped his hand.

Indra continued, "My chakra is the purest inheritance of the Sage Eyes. With it, the Mangekyō will no longer be an obstacle for you.

"But as for the Eternal Mangekyō… you'll have to figure that out yourself."

As he spoke, his body began to emit an otherworldly blue glow. The light flowed into Sasuke, merging with his spiritual pressure and resonating with his eyes.

"And the final step: the Rinnegan.

"My chakra alone cannot help you achieve it. But I know how it can be done.

"You'll need to obtain Asura's chakra.

"My father's power was split between me and Asura. I inherited the Sage Eyes, while he inherited the Sage Body.

"Only by combining our powers can you awaken the Rinnegan."

Indra's voice grew fainter as the glow intensified. His body became increasingly translucent, yet his expression radiated determination.

"Sasuke Uchiha, you've been blessed with extraordinary fortune.

"This other world…

"I believe you are the one who can finally surpass Asura.

"For me, for the Rinnegan, for ultimate power, and for the vengeance in your heart…

"Find Asura's reincarnation. And defeat him."