Deep within the mountains surrounding the Land of Rivers, inside a hidden base concealed among the wilderness, numerous mysterious figures dressed in black robes moved about busily. Around their necks hung silver pendants—circular on the outside, with a triangle engraved within.
"Shinji Akagi. Hidan. Once the blood extraction is finished, you will begin today's taijutsu sparring session."
"Yes, Lord Takihata."
Bang! Bang!
Inside a spacious underground chamber illuminated by flickering firelight, two figures clashed violently in hand-to-hand combat. The sound of fists slamming into flesh echoed continuously from the very start.
One figure would be knocked to the ground—only to immediately spring back up and retaliate.
And then the same would happen in reverse.
As the fight dragged on, their stamina drained rapidly. Their movements gradually lost any semblance of form or technique, until the battle resembled less of a martial contest and more of a test of sheer willpower.
One punch. One kick.
A brutal exchange to see who would be the first to stay down and never rise again.
Truth be told, the fight itself wasn't particularly spectacular or impressive.
The two boys appeared to be only fourteen or fifteen years old. Their taijutsu skills were far from refined, and their technique left much to be desired.
Yet if one looked purely at the raw power they displayed—their strength, resilience, and ability to absorb punishment—it was clear their physical abilities far surpassed the baseline of ordinary boys their age.
Because of that, even though the fight wasn't especially noteworthy, the black-robed observers surrounding them continued taking notes without pause.
After all, this wasn't a martial arts class.
It was merely another daily observation experiment.
"Alright, that's enough for today. Rest for one hour, then we'll begin your curse technique training."
The man who spoke appeared to be in his forties or fifties. Unlike the others dressed in black robes, he wore a dark red robe. A warm, gentle smile remained on his face at all times, giving him the appearance of a friendly countryside uncle.
But in reality, this seemingly kind and approachable man was the founder of the Jashin Cult—a man who built the organization with the doctrine of "endless slaughter."
While secretly expanding his influence, he also orchestrated relentless raids and massacres across nearby regions.
Over time, the very existence of the Jashin Cult had become a forbidden taboo throughout the Land of Rivers and beyond.
The two boys who had been about to smash their fists into each other's faces finally stopped. Their punches halted just centimeters away from the other's cheek.
"Tch. Lucky you this time. Otherwise that punch would've blown your head off first!"
The speaker was a gray-haired boy with purple-red eyes and slicked-back hair. A rogue ninja headband from Yugakure hung around his neck.
He glared angrily, muttering complaints under his breath.
If one ignored the fact that he was gasping for breath, with bruises covering his face and dirt clinging to his body, his words might actually have sounded somewhat intimidating.
Standing opposite him was another boy of roughly the same height. He had pale skin, short spiky brown hair, and a rather cold expression.
Yet his appearance was misleading.
Despite looking somewhat fragile, during the fight he had attacked with reckless abandon—as if he didn't care whether he lived or died.
His ferocity had been unsettling to watch.
And anyone who knew him a little better would realize that this seemingly gentle, handsome boy was anything but mild-mannered.
Quite the opposite.
He had an absolutely terrible personality.
Sure enough, the moment the other boy started boasting again, he responded in a quiet, mocking tone.
"With those honey-glazed soft bread fists of yours? If your goal was to sweeten me to death, then I have to admit—you succeeded, Hidan."
"Shin! Ji! A! Ka! Gi! You bastard! I'm going to kill you!"
Unable to win the verbal exchange, Hidan's eyes instantly filled with murderous intent.
"You dare describe my iron fists like that?! By Lord Jashin, you're dead today!"
"Oh, sorry. I really shouldn't have said that," Shinji Akagi replied casually. "After all, compared to those sissies who just pull hair and scratch faces, at least you don't cry for your mommy while getting beaten up."
Shinji Akagi refused to back down.
In fact, he leaned forward and pressed his forehead directly against Hidan's chest. With every sentence, he shoved forward harder.
Step by step, Hidan was forced backward.
His eyes turned increasingly red with rage.
Then Shinji raised his head again, revealing an expression that clearly said:
I gave you a chance—and you still couldn't do anything.
Hidan finally snapped.
"DIE!"
With a roar, he pulled a black short spear from his robes. Under the slightly helpless gazes of the onlookers, he drove it straight through Shinji Akagi's heart.
THUD!!!
Pain.
Unbearable pain.
Even though this wasn't the first time Shinji had experienced death, the agony of having his heart pierced was still vivid and excruciating.
But at the exact moment Hidan stabbed him—
Shinji's kunai flashed forward.
It plunged cleanly into Hidan's throat, burying itself to the hilt.
Clearly, Shinji had anticipated the attack from the start. Instead of dodging, he chose to launch a simultaneous killing blow.
This was a man ruthless toward others—
And even more ruthless toward himself.
Thump.
Both Shinji Akagi and Hidan collapsed backward.
One with his heart pierced.
The other with his throat sealed.
For any normal person, wounds like these meant certain death—even with immediate medical treatment.
Yet what was even stranger was the reaction of the people around them.
No one moved.
No one attempted to help.
They simply watched with cold indifference, their expressions unchanged even after witnessing the two die together.
Then, the next moment—
Hidan suddenly raised a hand.
Grabbing the kunai lodged in his neck, he yanked it out with force.
Splurt—CLANG!
"Cough! Cough—Gah! (Damn it, that hurts like hell!)"
Cursing internally, Hidan climbed back to his feet. The kunai he tossed aside was drenched in blood.
Yet he wasn't dead.
Not even close.
His wound was already healing rapidly.
On the other side, three seconds after his death, Shinji Akagi regained consciousness.
Under the gaze of everyone present, the supposedly dead boy suddenly opened his eyes.
He stood up smoothly, then casually pulled the black spear from his own heart and tossed it aside.
Since fate had inexplicably dragged him into this terrifying ninja world, then he would adapt however he had to—
Whether that meant killing others or being killed himself.
"Pah!"
Spitting out the bloody saliva in his mouth, Shinji Akagi—who had just died moments ago—immediately spoke again.
"That's it? Seriously? My grandma was stronger than you when she was still alive."
Hidan ground his teeth so hard they nearly shattered.
But there was nothing he could do.
After all, both of them had survived that ritual.
Both had gained a form of immortality—a blessing granted by Lord Jashin.
In truth, this wasn't the first time Hidan had killed Shinji Akagi in a fit of rage.
But every time, things ended badly for him.
Either they died together—or Shinji killed him in return.
Once, Hidan had even succeeded with a sneak attack.
But afterward, Shinji retaliated with terrifying vengeance.
The horrible feeling of having his head cut off and buried underground was something Hidan absolutely never wanted to experience again.
Back then, hundreds of Jashin Cult members had spent three days and nights playing a twisted "treasure hunt," searching for his missing head.
In the end, it was only after Cult Leader Takihata lost his temper that Shinji finally pointed toward a tree where it had been buried.
From that moment onward, their feud was firmly established.
It also made many members of the Jashin Cult reconsider just how terrifying Shinji Akagi's personality truly was.
That was one of the reasons why Hidan had mostly stuck to trash-talk earlier.
Only when pushed too far had he finally resorted to violence.
Because under normal circumstances, anyone who dared talk to him like that would've already been torn into pieces.
"This boring little game is over, children."
The cult leader Takihata finally spoke, having watched the entire spectacle without interfering.
"You both seem to have plenty of energy left. In that case, your rest period is canceled. Head to Chamber Two immediately—the materials are already prepared."
In truth, the reason he had allowed their feud to continue was simple.
Thanks to their constant attempts to kill each other, the cult had collected an enormous amount of valuable experimental data in just one month.
Knowing further fighting would accomplish nothing, Hidan snorted coldly and turned away.