Another slash flashed through the dark.
A shallow wound opened across the Amegakure ninja's leg. It wasn't fatal—nowhere near it. By all rights, he should have been able to dodge an attack that straightforward from a child.
But at the crucial instant, his body had stiffened.
"That brat's blade..."
The Rain shinobi narrowed his eyes.
The scalpel in Yubi's hand was so thin it could disappear against his palm, yet its edge was unnervingly sharp. Being wounded twice by a genin was humiliating enough to make rage boil up in his chest.
Even so, Yubi didn't press the advantage.
The moment he forced the man back, he spun around and shot toward his injured teammate lying farther away. In the blink of an eye, he scooped the boy up and retreated.
"Hm?"
Only then did the Rain ninja realize something was wrong.
The numbness in his limbs was getting worse. The stiffness spreading through his body was no longer subtle.
"Poison..."
His pupils contracted.
If one spoke of poison users across the entire shinobi world, Sunagakure was almost impossible to avoid. Hanzo of the Salamander was also famous for his venom—especially the terrifying poisons he used alongside the black salamander, toxins so dreadful even Konoha's Legendary Sannin had suffered beneath them—but Hanzo was a single monstrous exception.
Sunagakure was different.
That village's puppet masters relied on traps, mechanisms, and toxins as naturally as other shinobi relied on kunai and wire. The poisons of the Sand were not necessarily the deadliest in raw potency, but when it came to using poison efficiently, ruthlessly, and precisely, few could compare.
The Rain ninja's expression hardened.
"Still... this level of poison won't be enough."
Before the numbness worsened, he immediately widened the distance again, trying to stall for time. After all, he had been personally tempered under Hanzo's system. Against toxins that were not overwhelmingly lethal, he had a measure of resistance.
"Stop wasting your effort," Yubi said, his eyes cold and steady. "You're already dead."
The words were so calm that they sounded almost indifferent.
Then, without lingering another second, Yubi carried his companion and leaped away.
"Arrogant little bastard!"
The Rain shinobi gritted his teeth.
But before he could give chase, an abrupt dizziness struck him. Strength drained from his body in a sudden wave, and his vision blurred at the edges.
Not poison.
His gaze dropped.
The slash on his leg—seemingly minor a moment ago—had bled far more than he had realized. Blood had been pouring out the whole time, and in the heat of battle he hadn't noticed how quickly his body was weakening.
Thud.
He collapsed heavily to the ground.
So I actually lost... to a rookie?
That bitter thought flashed through his mind just before consciousness deserted him.
***
With his injured comrade on his back, Yubi bounded across the rock face until he reached a high platform carved into the cliff. From there, the battlefield below lay spread out in a single glance, and the distance gave him a momentary pocket of safety.
He set the boy down and looked him over quickly.
The explosion had mangled the right side of his face. One eye was obviously gone. There were burns, torn flesh, and missing pieces from both his hands and one leg.
The boy's breath trembled. "I'm sorry... Yubi... I'm only slowing you down. Leave me. You're a medical ninja. You have to escape first and send the intel back."
"It's fine," Yubi said, already kneeling beside him and working with swift, practiced movements. "There aren't many enemies. Endo-senpai is still holding them off for now."
He smiled faintly as he spoke, but the corner of his vision remained fixed on the battle below.
The situation was awful.
The enemy raiding unit had only three people left, counting the one from Amegakure that Yubi had just dropped. On their side, however, only Endo was still fighting. Another genin and the wounded chunin had already died.
From the moment the ambush began until now, less than five minutes had passed.
That was how small-scale shinobi combat worked. It wasn't like the roaring chaos of a battlefield where armies clashed head-on. In fights like this, life and death could be decided in a blink.
Logically, as a medical ninja, Yubi should have followed the rules drilled into him from the academy and prioritized his own survival above all else. But the circumstances were no longer normal.
No one here had the luxury of protecting him first.
"Rest for a bit," he said after finishing the emergency treatment.
The injuries were too severe to solve on the spot, but he had stopped the worst of the bleeding and stabilized the boy enough to keep him alive for the moment.
Then Yubi rose and turned back toward the battlefield.
He meant to help Endo.
This strike team looked like Hanzo's elite, but after crossing blades with one of them, Yubi had made a rough judgment. The enemy was dangerous, yes, but not untouchable. If he and Endo fought together, there was still a chance.
Even if he was only a genin.
With that thought, he moved.
***
"Hm?"
Down below, the Rain shinobi noticed him at once. The expression on all three of their faces shifted.
"That brat from the Sand is still alive?"
"Aoki's dead?"
"Pathetic. He couldn't even deal with a genin."
Their voices were full of cold contempt.
"Run!" Endo shouted the moment he saw Yubi charging back in. "What are you doing here?!"
Yubi ignored him.
"Observation complete," he murmured under his breath. "The sample size is sufficient."
He rushed straight toward the enemy without the slightest hesitation. His gaze flicked from one opponent to the next, measuring posture, breathing rhythm, center of gravity, wounded areas, reaction speed.
Then he locked onto a target.
As a transmigrator, Yubi knew this world far too well.
He knew the major shinobi villages, their bloodlines, their habits, the rough structure of their combat systems, even the styles different ninja types tended to rely on. It was like having a fragmented database in his mind—imperfect and incomplete, but still valuable.
Yet that was not his greatest advantage.
His real trump card was what he had gained through the system: the knowledge and insight inherited from Black Jack. That terrifying archive of medical understanding had given him an almost surgical awareness of the human body.
Bones. Tendons. Blood vessels. Muscle groups. Joint limitations. Recovery thresholds.
He had trained with that knowledge long before entering the Ninja Academy.
He used his own body as a test sample, pushing it to the limit, breaking it down, then recovering faster than ordinary children ever could thanks to his medical skill. Time and again, he wore himself out completely, restored himself, and started over.
It was a crude but effective way to temper a body.
And as a doctor, he held another advantage ordinary shinobi lacked.
From the way a person moved, he could estimate the condition of their muscles and joints. From the angle of their stance, he could infer the range of their offense and defense. From subtle asymmetries in motion, he could identify old injuries, weaknesses, even hidden trouble within the body.
Using all of that—his medical knowledge, his own physical conditioning, and the fragmented data he carried in his head—Yubi had built a combat method that suited him best at this stage.
He called it data body technique.
At least for now, it was enough.
Even the poison he used had been prepared by his own hand.
Yubi lowered his center of gravity and was just about to engage.
Then the battlefield changed.
Without warning, several puppets dropped from the darkness above.
They descended so abruptly that it was as if they had materialized out of thin air beside the three Rain shinobi.
The puppet on the left was humanoid. As it lunged forward, its mouth snapped open and spat out a sharp metal spike that pierced straight through one enemy's skull.
The puppet on the right was also humanoid, but one of its arms had transformed into a high-speed rotating blade. The next instant, it carved through another Rain ninja's waist and sliced him in two.
The last puppet looked like a crawling lizard.
When it reached its target, the plates along its back sprang open, revealing dense launch ports beneath. A storm of poisoned needles erupted outward and riddled the final enemy from head to toe.
The entire exchange happened so fast that Yubi's charge came to an abrupt stop.
A battle that had seemed savage and desperate only a second ago ended in a blur.
In the distance, someone landed lightly on the rocks.
A young figure walked forward with measured, unhurried steps. Fine chakra threads swayed from his fingers beneath the dim light, delicate and deadly all at once.
Sasori.
Yubi quietly slid the scalpel back into his pouch, unsurprised.
This was what a genuine monster looked like.
The Amegakure ninja they had fought were not especially famous, and shinobi rank alone could never truly define battle strength. On the vastest battlefields, perhaps these Rain ninja were little more than expendable pawns.
But for them—for a squad made up of a chunin, a few fresh graduates, and one injured man—they had been more than dangerous enough.
And yet Sasori had erased them in an instant.
Eight years old sounded absurdly young.
But in this world, there were always a handful of people who shone too early, too fiercely, as though ordinary standards had never applied to them at all. Once they revealed themselves, no one of the same generation could hope to stop them.
Compared to those monsters, the endpoint many people spent their entire lives struggling toward was often nothing more than the place those geniuses began.
Sasori walked over slowly, withdrew his puppets, and finally lifted his eyes toward Yubi.
"I thought that with you here," he said in a flat voice, "nothing would happen."
He completely ignored Endo and spoke only to Yubi.
Yubi let out a breath. "You think too highly of me."
Sasori said nothing.
He only stared.
His gaze was quiet, unwavering, and unnervingly deep—as if he were trying to see straight through Yubi himself.