The Land of Rain.
A strategic checkpoint along the border.
This place had become a blood-soaked prize, a contested ground between the great nations.
To claim control over it, Iwagakure and Konohagakure had clashed here over a hundred times.
Corpses piled like grotesque monuments, blood flowing thick enough to dye the river crimson.
On broken tree trunks, charred and blackened arms still hung, while the scorched earth hissed with lingering embers.
Among the sea of corpses, a frail, hunched silhouette moved hesitantly, searching for survivors.
The boy wore a short gray shirt, and a hitai-ate of Konohagakure was tied tightly on his forehead, its spiral emblem soaked in blood.
His face was masked with streaks of dried, blackened blood, his features unrecognizable.
Judging by his size and build, he was no more than a teenager, a child forced onto a battlefield.
One of his arms was gone, blown away.
After clumsily stopping the bleeding, he resumed his search through the slaughter.
At most, he was fifteen years old.
Yet at this age, he had already endured more than ten large-scale battles.
"Are you… still alive?"
Rin Uchiha crouched beside a corpse, lightly patting its cold, stiff shoulder, his voice hoarse and low.
He tried again, shaking the body, but no answer came.
The pale, lifeless eyes stared back at him with a chilling silence.
He hadn't even known this comrade for long.
He hadn't remembered their name.
Yet the memory of laughing conversations on the march was still fresh in his mind.
Rin's vision dimmed, his eyes drowning in grief.
The battle was over.
There was no one left alive around him.
The Uchiha clan's fifty warriors, sent to this front, had all perished.
They never even reached the rendezvous point of their mission.
They were ambushed halfway, caught in a trap.
Four jonin, twelve chunin, and all the rest genin—every single one was dead.
A force like this should have been nearly impossible to wipe out.
Yet now, he alone survived—a mere medical genin.
Rin let out a bitter laugh, hollow and sharp like shattered glass.
"Why didn't you listen to me?"
"You trusted the village too much… obeyed their orders without question, walking straight into this battlefield."
"In just one stroke, the clan has lost so many of its best shinobi. How will we face the village's schemes now?"
"All of my comrades died here."
"Then why… why am I the only one left alive?"
"How am I supposed to face your families…?"
His mind began to unravel.
In his last memory before collapsing, their unit had been caught in an ambush by Iwa shinobi.
The road ahead had been littered with explosive tags, detonating all around them.
The enemy didn't even show themselves before half their force was torn apart.
He remembered the sharp, blinding pain as his left arm was ripped away… then darkness.
Judging from the battlefield now, the Uchiha jonin captains must have fought to the death, slaughtering every last enemy before falling.
In the center of the field, Rin recognized the corpse of one of their squad leaders—surrounded by over a dozen dead Iwa shinobi, a testament to his final stand.
But Rin… Rin hadn't died.
Was that really luck?
Why couldn't he have died with them?
He was a transmigrator—someone who had already died once.
Another death would have been a release.
He wouldn't have to endure the agony of surviving, the hollow gazes of grieving families, or the suffocating weight of guilt and loneliness.
Rin slowly raised his remaining right hand, eyes catching something strange.
Was it just the hallucination of a mind frayed by war?
A beam of light appeared before his eyes.
"Flesh Ascension Protocol successfully bound."
"Beginner reward granted."
"Congratulations. You have acquired the golden skill: [Evolution Calculus]. You can perform evolutionary computation on a genetic sequence. Each computation consumes 10 points of mental energy."
"Main quest [Evolution] unlocked. From now on, your body can undergo genetic evolution, advancing to higher life stages. Current stage: First Tier [Flesh Embryo]. Next stage: [Cellular Nebula]."
"Advance your life stage as soon as possible."
"Developer's note: Life eternal, flesh ascends!"
"Evolutionist No. 1325, commence your research."
Evolutionist Panel:
Name: Evolutionist – Rin Uchiha
Evolution Level: [0/10]
Gene Plugins: None
Special Genes: [Otsutsuki Gene] (Fragmented · Hidden), [Tree Chakra Gene] (Fragmented · Hidden)
Physical Ability: [E]
Mental Ability: [D]
Power Rank: Chunin (Level 2)
"A system…?"
Rin hesitated, bewildered. He had been living in this world for so long, he had almost forgotten what it felt like to be someone from another life.
He had already become one of the Uchiha, raised among them, feeling their pride and warmth.
He had nearly forgotten that in his past life, he had been a doctor.
This world resembled the Naruto he once knew, but he had never encountered any familiar faces.
To him, the Uchiha were no longer fictional characters on the pages of a manga.
They were his family—living, breathing, laughing, crying, loving, and fighting.
After over a decade in the closed-off Uchiha compound, Rin's heart fully accepted this clan as his own.
His talent had always been average, but with the help of his past life's medical knowledge, he mastered the theoretical side of medical ninjutsu.
After completing the clan's training program, he became an intern medical-nin at Konoha Hospital with the clan's recommendation.
When he joined the hospital, Tsunade had already left the village.
He never got to see her.
Instead, he trained under an ordinary medical-nin instructor.
It was simple, stable work—a far cry from his previous life as a doctor who had to pay to practice.
Here, the clan even gave him a stipend.
After graduation, Rin became an auxiliary medical-nin.
But when the war erupted, the frontlines were desperate for reinforcements.
He stepped in to take the place of a neighbor's granddaughter on a support mission.
The neighbor was Uchiha Setsuna, whom Rin had never met, but he was close with Setsuna's granddaughter, Uchiha Izumi, treating her as his own sister.
Once Iwagakure declared war, Konoha's forward units were under immense pressure.
The Uchiha clan head responded by sending a contingent of clan shinobi to bolster the village's defenses.
The squad was led by one of the clan's elder councilors—a veteran known for his pacifist stance.
Despite years of Konoha's suppression, the elder accepted the mission without hesitation.
Before they departed, Rin had tried to warn him.
He feared their squad's route would be leaked by certain figures in the village, but the elder dismissed his concerns, even scolding him for speaking such things.
Now the result was here: total annihilation.
Only Rin remained alive, saved by this strange system.
They hadn't even completed their first mission on the field before falling into Iwa's ambush.
The unit was obliterated.
Rin stared at the carnage, his mind sinking into a pit of despair.
Even with this newfound power, there was no joy, only guilt.
If the system had come earlier…
If he had been stronger…
Perhaps his clan wouldn't have died so miserably.