Reborn In The World Of Naruto

Ryuuji stood frozen, his mind racing as he tried to process what he had just witnessed. The overwhelming display of his grandfather's power, the revelation of Chrono Domain, and the implications of such an ability left him spiraling in a vortex of awe and disbelief.

'Chrono Domain? What kind of ability is this? Is it similar to Kamui?' he thought, his mind involuntarily comparing it to the legendary Mangekyo abilities he remembered from the original series.

But this was different. Terrifyingly different.

Ryuuji's gaze flitted around the dome of shimmering blue light. It was as if the very fabric of reality inside had been twisted. The air felt heavier, more deliberate, each moment stretched like a taut string ready to snap.

'Edo Tensei Madara with his Eternal Mangekyo Sharingan was stronger than all five Kage combined,' Ryuuji mused, his thoughts growing increasingly frantic. 'He wasn't just Kage-level; he was beyond it, standing as a true peak powerhouse in both Energy Cultivation and Body Cultivation. But this… this is on another level entirely.'

His body shuddered as his mind drew a chilling conclusion.

'If Grandpa also possesses the Eternal Mangekyo Sharingan, doesn't that mean… doesn't that mean he's at least a Peak-level Kage-stage powerhouse too?' The very thought sent a chill down his spine.

"Ryuuji," Jima's voice snapped through the haze of his thoughts, pulling him back to the present.

Ryuuji turned to face his grandfather, the man who now seemed less like the cheerful elder he'd known up with and more like a titan, a being whose strength rivaled the Legends of the Original Series themselves.

Jima's gaze was steady, his aura radiating a calm authority. "You seem overwhelmed," he noted, his tone light but carrying an undertone of amusement. "Let me explain. What you just saw is my unique Mangekyo ability: Chrono Domain. As you might have guessed from the name, it's an ability tied to time and space itself."

Ryuuji nodded, his throat too dry to form words. The name had been a dead giveaway, but hearing Jima confirm it made the reality hit harder.

"In this space," Jima continued, gesturing around them, "time moves much faster than it does on the outside."

Ryuuji's eyes widened at the revelation, his mind already spinning with possibilities and, admittedly, a bit of fear. 'Faster inside than outside? That means...' His thoughts darkened as a terrible realization struck him.

'If I stay inside the Chrono Domain too long, will I age faster? Is that why Grandpa asked me earlier if I'd be willing to sacrifice my life to grow stronger? Does this… reduce lifespan?'

His mind churned, but before he could spiral too deeply, Jima spoke again, almost as if he had plucked the thoughts right out of Ryuuji's head.

"It depends on me," Jima said, his tone calm but firm, "how much area I want the domain to cover and how fast time moves within it."

Ryuuji blinked, his jaw dropped slightly as he blurted out, "Holy Six Paths! Grandpa, did you just read my thoughts?!"

Jima let out an exaggerated sigh and rolled his eyes. "You dumbass, your thoughts are written all over your face."

Ryuuji's cheeks turned beet red as embarrassment washed over him. He couldn't believe he had been so obvious. He cleared his throat awkwardly, trying to recover some semblance of dignity.

But then, another thought struck him—one that made him pause. His brows furrowed, and he looked at Jima with a mixture of confusion and curiosity.

"Grandpa," Ryuuji began cautiously, "doesn't each Mangekyo Sharingan wielder only have one unique ability? Why do you have two?"

The question was fair. Chrono Domain itself was a game-changer, but the fact that Jima could seemingly manipulate the space and time within it at will was on another level of absurdity.

'The only other person who had two Mangekyo abilities was Sasuke in the original series,' Ryuuji thought to himself. 'His left eye could cast Amaterasu, while his right eye allowed him to manipulate and extinguish those flames with Kagutsuchi. But Sasuke was the reincarnation of Indra Otsutsuki! Does that mean... Grandpa is as much of a genius as Sasuke?!'

Jima's answer was surprisingly simple. "Honestly? I have no idea why. It's been like this ever since my Sharingan evolved into the Mangekyo."

Ryuuji's eyes widened in amazement. 'A natural genius on the same level as Sasuke?!' His awe only deepened.

But then, another thought took hold, one that made him grin inwardly. 'Wait a minute. I'm not being narcissistic, but with the System, aren't I a bigger genius than Sasuke? Then doesn't that mean it's almost guranteed that I will surpass both Grandpa and Sasuke? Hell yeah!!'

His chest swelled with pride at the thought.

But that pride quickly tempered itself with resolve. 'Still, I can only surpass them if I stay alive long enough. I need to train diligently, push myself to the limits, or I'll end up like Minato, Yahiko, and Itachi—dying before reaching my true peak.'

"Anyways," Jima's voice pulled him from his thoughts once more.

"Where was I? Ah, yes," Jima said with a slight smile. "I was explaining my abilities. With my right eye, I can use Chrono Domain. With my left…" He paused dramatically, the air around them growing heavy with suspense.

"I can use Nexus Sovereignty."

The words hung in the air like a thunderclap, their weight sinking into Ryuuji's chest.

"Nexus Sovereignty," Jima continued, "allows me to modify the Chrono Domain further. I can reduce its size, anywhere between one kilometer and ten kilometers, and I can increase the time dilation ratio. For example, I could make one year inside the domain equal to one month outside. That's the ratio I'll use to train you."

Ryuuji's jaw dropped. His mind raced as he tried to wrap his head around the implications of such an ability.

"However," Jima said, his voice dropping to a more serious tone, "increasing the time dilation comes at a cost. The greater the ratio, the more chakra it requires. Even for me, pushing it too far could drain my reserves completely. And at my age…" Jima trailed off, his expression momentarily somber.

'Not that it matters anymore,' Jima thought to himself, a flicker of melancholy crossing his features.

Ryuuji's eyes sparkled with admiration. "Grandpa, you're amazing!"

Jima grinned, his usual humor returning. "Of course I am! Your grandfather is the second strongest being alive! Hohohoho!"

Ryuuji froze. His excitement dimmed slightly as confusion set in. "Wait… second strongest? Who's the first?"

'Is it Kaguya? He even knows about her existence!? Is Grandpa also a reincarnated soul!?'

At this, Jima's laughter faded, and his expression grew grave. The air around them shifted, the weight of his seriousness pressing down on Ryuuji like a physical force.

Jima's gaze sharpened, his lips forming a thin line. His voice was calm but carried an unmistakable edge.

"The first…" Jima said, his tone dark, "is someone you're not ready to know about yet." 

***