The Uchiha Massacre Night—it no longer felt like anything important.

Gazing at the crescent moon slowly rising over the horizon, Uchiha Kirin suddenly felt a strange emptiness in his heart.

For the past three years since arriving in this world, he had worked tirelessly toward this goal. And now, somehow, without even realizing it, he had accomplished it perfectly.

He lay on his bed, staring up at the night sky through the roof.

"I wonder... beyond the Shinobi World, just how many other worlds are out there? And what are they like?"

As these thoughts crossed his mind, an overwhelming drowsiness took hold.

Uchiha Kirin felt like his mind had turned to mush—like it had been tossed into a washing machine and spun for millennia. Even with his tremendous spirit, he couldn't fight off this level of fatigue.

"Sleep," he sighed deeply, the only thought in his mind now being rest. He stopped thinking about running more simulations...

...

At sunrise, peace blanketed the Uchiha district.

Some early-bird shinobi were already heading out on missions, and food vendors had begun setting up their breakfast stalls. Curling wisps of smoke rose from every home.

Birds chirped joyfully, filling the morning air with their lively song.

...

Suddenly, an awful screech of a cat jolted Uchiha Kirin awake.

Opening the window, he scooped up the black cat he had only just met yesterday—Boss Black—and brought it inside, burying his nose into the cat's fur for a deep sniff.

"Smells like shampoo… Little Black, huh? Didn't expect you to get a spa treatment last night."

"Mrowngh!"

The black cat let out a stiff, pinched meow that almost made Kirin yank his ears off.

He held the cat close and gently rubbed its fur. Boss Black gradually began to accept this "human child" who was actually more terrifying than any giant summoning beast.

...

"So tired..."

For some reason, even as he looked at the rising sun, Kirin still felt drained in both body and mind.

But he had gone to bed quite early last night.

And with the strength of his current body and spirit, even if he released a million Shadow Clones to spar with each other for days on end, the accumulated fatigue wouldn't leave much of a dent.

And yet, there was another strange thing he noticed.

His temperament had clearly become much calmer than before—almost to the point of feeling... aged.

Back when he was desperately running simulations just to survive, he hadn't paid it much attention. But now that he had stopped to rest, this shift in his personality felt especially pronounced...

"Could this be... a side effect of the simulations? System!"

Ding! Continuous simulations can lead to mental fatigue. This is normal.

The simulation's mechanism is related to the theory of parallel worlds. From this perspective, everything experienced in the simulation is something the user undergoes personally. While memories of the events are not retained, they do leave subconscious and physical imprints...

"So that's it. Are there any hidden dangers?"

Ding~ The user and the simulated self are the same entity. Aside from mental and physical strain, there are no other side effects.

Therefore, the assistant does not recommend prolonged simulator use to ensure the user's physical and mental well-being.

Reading this, Uchiha Kirin felt many of his doubts ease.

No wonder that after some simulations, just reading the processed system text would trigger deep hatred toward certain characters.

So much so that in the next simulation, he would go out of his way to exact revenge on them…

"Looks like I really do need a proper rest..."

He shifted his focus to a mosquito clone that was still watching over Obito. Since Obito wasn't doing anything suicidal at the moment, Kirin decided to let it be for now.

He'd deal with all that once he was fully rested.

So, he created a Wood Clone whose face screamed bitter resentment and sent it out to take his place in daily activities.

As for his real body, he wrapped himself tightly in a blanket, stuffed Boss Black inside, buried his nose into the fur again, and passed out on the spot...

...

A week later.

The fatigue had slightly eased. Uchiha Kirin finally woke up.

Rubbing his head and splashing cold water on his face, he stood before the basin with a dead look in his eyes.

"Slept that long and still feel like crap?"

It felt like every cell in his body was protesting—complaining about how many times he had run simulations in just one day.

Luckily, his body's current endurance was absurd. If he had still been the original Uchiha weakling, even developing a Kekkei Genkai illness would've been a blessing compared to what he'd gone through.

Still, even after sleeping this long, his entire body rejected any strenuous movement.

Because... his physical structure was far from human. His number of cells far exceeded 130 trillion.

While maintaining human form, most of his cells would enter a dormant state, compressing his body into a normal appearance.

But strictly speaking, it was only when he shifted into his serpentine form that every cell in his body could fully stretch and activate. That was when all of his attributes were fully unleashed...

So, while these cells gave him strength beyond even elite shinobi—and even the average Ōtsutsuki—they also required far more rest and energy to sustain.

In short—

To fully recover both physically and mentally,

He needed to use his serpent form to reactivate his dormant cells, and rest in a place rich in natural energy to replenish himself.

"System, can I use the simulator to recover?"

Ding. The simulator can only be used to deduce future outcomes and boost power. It does not have a recovery function.

"Tch, figures."

Kirin shook his head, then a new idea popped into his mind—head to the sea.

Just like the land, the ocean also had Dragon Veins. In fact, due to less human interference and far greater area, the sea likely held even more abundant natural energy—perfect for recovery.

Moreover, the Land of Water had more Kekkei Genkai users than any other place in the Shinobi World. Even if you excluded bloodlines from the Ōtsutsuki Clan, it was still unmatched.

This indicated extremely dense natural energy in the area, which allowed local shinobi to develop all kinds of unique Kekkei Genkai.

Take Jūgo, for example—his clan lived near the Ryūchi Cave entrance, and prolonged exposure to natural energy led them to develop Sage-like bodies.

Kirin speculated that the origin of all these Kekkei Genkai in the Land of Water was likely the same. There must be a Dragon Vein there, exposed to the surface—but unlike the one at Ryūchi Cave, this one wasn't so volatile.

If it was unclaimed, he'd take it. If it had a master… well, he could always steal it. Either way, it would serve as both a training ground and a resting place in the future.

And come to think of it, even though he'd spent long periods in ocean environments during simulations, he had never actually seen the real ocean in this life.

No hesitation.

He flipped open the Sealing Scroll of Techniques and found the page containing the Flying Thunder God Technique.

Then he instructed his mosquito clone—still watching Obito—to carve a unique Flying Thunder God marker on the cliff wall.

Boom!

A massive serpent body burst into the cave where Obito and Black Zetsu were hiding—the same place Uchiha Madara had once used as a base.

In Obito's stunned gaze, Kirin transformed into a gigantic white serpent, storming straight toward the area where Madara's legacy was stored.

Obito tried to phase through the attack, but then—red light flashed in Kirin's eyes. Six tomoe slowly rotated.

Kamui failed to activate.

With a crack, Kirin's tail struck Obito midair, slamming him into the stone wall.

Blood splattered across the ground.

Uchiha Kirin had never been one for dragging things out.

This early reckoning—had already begun.