The canyon outside the cave had already descended into chaos by the time Yubi and Sasori finished waiting for Endo.
A Sand ninja appeared at the entrance and looked at the two boys with a grave expression. "You two, come with me."
Yubi traded a glance with Sasori. Neither of them asked any questions. They simply followed.
All throughout the canyon, the signs of battle had multiplied. The clash of steel, the boom of exploding tags, and the wind-swept echoes of shouting rolled through the stone corridors without pause.
Sand shinobi were appearing everywhere now, rushing through the valley toward the source of the fighting.
Before long, Yubi and Sasori joined a larger group at the base of one of the ravines.
There were more than twenty of them gathered there.
This was not all of Sunagakure's manpower in the area, only the forces that could be assembled quickly. Many of the more experienced ninja had already been sent ahead to intercept the Amegakure units that had appeared in the canyon.
The rest were either not suited for direct combat or had duties too important to abandon.
Yubi spotted a few familiar faces in the crowd. Just like him, they were fresh graduates from the Ninja Academy.
Those genin were visibly rattled.
For them, this was no training exercise and no routine mission. This was a real battlefield.
The man addressing them wore a white headscarf wrapped around his head. His posture was taut, his voice steady, and the chakra pressure around him marked him clearly as a jonin.
"My name is Takuma," he said. "I am the commander of this engagement, and your temporary captain. Due to an unexpected breach, shinobi from the Land of Rain have broken through the front line and infiltrated this area. Their exact purpose is not yet confirmed, but according to the intelligence we have, they most likely intend to gather information on our border defenses."
His eyes swept across the assembled ninjas.
"Which means that no matter what, we must kill every one of them and cut off that hope at the root."
The air in the valley grew heavier at those words.
Yubi stayed silent and listened.
Takuma did not waste a second. "Medical ninjas, step forward."
Including Yubi, seven people moved out from the formation.
That was all the medical support Sunagakure could spare for the rear border positions.
"Logistics and intelligence personnel, step forward."
Several more shinobi answered.
Takuma pulled out a rough map and pointed to a few marked sections with two fingers. "The canyon has already become a fragmented battlefield. Medical teams and support personnel will split up and move to the corresponding combat zones."
"Your mission is simple. First, reduce casualties as much as possible. Second, no matter what happens, intelligence takes priority."
He paused, then looked at the others.
"The rest of you are responsible for protecting the medical teams."
His finger tapped the map again.
"This is our territory. There are hidden outposts throughout the canyon stocked with emergency supplies. Even if you run into the enemy, you can use the terrain and fight a mobile battle."
"Yes!"
The response rang out in unison.
Then the groups began to form.
Takuma's gaze shifted toward the boy standing beside Yubi. "Sasori..."
Among everyone gathered here, one person was clearly different from the rest.
Even as a child, Sasori could be counted as a major asset.
Takuma's plan for him was obviously not the same as his plan for the others. He wanted Sasori placed on the offensive, sent directly into the fighting to kill Amegakure shinobi.
But Sasori spoke before he could say more.
"I'm with Yubi's group."
Takuma paused.
It was obvious that he knew Sasori well enough to understand that arguing would get him nowhere. After the briefest silence, he nodded.
"Fine."
Then his tone sharpened.
"Move out!"
The formation broke apart at once.
Yubi's newly assigned team had five people.
Two were medical ninjas. One was an intelligence ninja. Sasori and a chunin made up the remaining combat protection, with the chunin serving as their temporary captain.
As they moved, Yubi's thoughts flickered back to the squad he had originally joined.
Nomura and the others were probably dead.
On the very first day they arrived at the border, almost everyone assigned to their patrol team had already disappeared.
Cruel did not even begin to cover it.
Yubi glanced sideways at Sasori as they ran.
Takuma had wanted him on the front lines, yet Sasori had chosen to remain with Yubi's squad instead of charging straight at the enemy.
Are you trying to observe me? Yubi wondered.
That possibility did not bother him.
Whether Sasori was acting out of curiosity or some other motive, getting closer to him was something Yubi had wanted from the start.
In Yubi's plans for changing Sunagakure's future, Sasori was too important to ignore.
Under the chunin captain's orders, their squad headed toward one of the active battle zones within the canyon.
They were not there to engage directly.
Their battlefield was a center point. From there, they were to sweep outward, search for the wounded, and observe the positions of scattered enemy shinobi moving through the canyon.
The five of them advanced separately, but never so far apart that they could not react to a disturbance.
Very soon, Yubi found an injured Sand shinobi.
He stopped sharply, crouched beside the unconscious man, took one look at his condition, and immediately opened his medical kit.
For most medical ninja, field treatment under these conditions was extremely difficult.
In the wilderness, without proper equipment or a secure operating space, medical ninjutsu did most of the real work. Drugs and tools alone had limited effect, especially in battles between ninja, where the injuries were rarely light.
Once someone went down on the battlefield, it was often very hard to get them back up again with ordinary treatment.
But Yubi's medical kit was different.
Along with bandages, scalpels, and ordinary instruments, it contained several medicines he had prepared himself. Most of them were antibiotics. Only a small portion were poisons.
The medical standards of the current ninja world were nowhere near those of modern society.
As a transmigrator who had inherited Black Jack's vast knowledge and surgical instincts, Yubi could use the ingredients and pharmaceuticals available in this world to refine his own remedies.
That was one of the reasons he stood out so much.
His hands moved quickly and without hesitation.
In just a few minutes, he had cleaned and treated the wounded man's external injuries. Then he administered an antibiotic injection and a nutrient solution he had prepared beforehand.
Throughout the treatment, Sasori stood a short distance away and guarded him.
His eyes lingered on Yubi's pouch.
What is that?
Even though Sasori was not a doctor, he could tell that some of the tools Yubi had just taken out were strange. Small, precise, unfamiliar. They looked nothing like the standard medical supplies used in the village.
Most of them were homemade.
After finishing, Yubi exhaled and looked toward him with a slight smile. "Please take him to the nearest outpost."
Sasori said nothing.
He simply flicked out chakra threads from his fingers and, as if manipulating a puppet, lifted the wounded shinobi and carried him away.
Yubi remained where he was for a brief second, then rose and continued after the team.
Before long, Sasori returned.
Fast.
Very fast.
From then on, the pattern repeated itself across the canyon.
Yubi kept finding wounded shinobi and treating them as quickly as he could. Some were unconscious but still breathing. Some were awake but too badly injured to keep fighting.
And more than a few were already corpses.
As long as there was still breath left in the body, Yubi could do something.
But given the current limitations, he could not restore most of them to full condition. He could only stabilize them, keep them alive, and buy them time.
Even so, his performance left a deep impression on everyone in the squad.
That included the other medical ninja traveling with them.
In that man's eyes, this boy named Yubi was nothing less than a medical prodigy.
And more than that, he had experience.
There was no panic in his movements, no hesitation in his diagnosis, no confusion in his hands. At times, his composure was so complete that people forgot he was just a child.
But if there was one person in the team more dazzling than Yubi, it was Sasori.
During the course of their mission, encounters with Amegakure shinobi were inevitable.
And every single time, the result was the same.
Sasori killed them.
Almost without exception, the enemies who crossed paths with their squad died by Sasori's hand alone.
It could be said that one person was carrying the entire security of the team on his shoulders.
As they moved deeper through the battlefield, Yubi's thoughts never stopped turning.
This canyon really was well suited for concealment.
Amegakure had chosen their route well. Their plan had been clever. What they had not expected was Sunagakure's response speed once the breach was discovered.
Judging by the scale of the fighting, the number of bodies, and the frequency of enemy contact, Yubi estimated that at least one or two hundred Amegakure shinobi had infiltrated the canyon.
The battlefield itself was not especially large, but that only made every clash more concentrated.
And to Yubi, that meant something else entirely.
This incident... might let him earn a huge amount of experience points.
The thought flashed through his mind, and for the first time since the fighting began, a quiet thrill stirred under his calm expression.
This is far better than interning at the hospital.
His pulse remained steady. His hands remained clean and precise.
But inwardly, Yubi was already measuring the wounded, the dead, the chaos, and the opportunities hidden inside all of it.
For a doctor in a war like this, every battlefield was a training ground.
Every life dragged back from the brink meant experience.
And every point of experience meant the possibility of becoming stronger.
Much stronger.
In a village as fragile as Sunagakure was now, that mattered more than anything.
So while the canyon boiled with battle, Yubi lowered his head over the next wounded shinobi, opened his kit again, and went right back to work.
Because this war, terrible as it was, had finally given him exactly what he needed.