The reinforced door opened with a deep mechanical rumble.
Behind it, a narrow stone staircase descended beneath the Konoha Research Institute. Small lamps embedded in the walls cast a pale glow across the steps, but their light failed to reach the bottom.
Tsunade entered first.
Ren followed without hesitation.
The air became colder with every step. The ordinary sounds of Konoha gradually disappeared until only their footsteps remained, echoing through the underground passage.
Several sealed doors stood along the corridor below. Each bore a different identification code, along with warning symbols indicating restricted materials, dangerous experiments, or chakra-sensitive equipment.
Tsunade continued until she reached the final door.
She pressed her palm against a circular seal carved into the stone. Chakra flowed from her hand, causing dozens of intricate lines to spread across its surface.
A hidden locking mechanism activated.
Metal scraped against stone, gears turned inside the walls, and the heavy door slowly slid aside.
The smell of old paper drifted through the opening.
Beyond it lay an enormous underground archive.
Rows of bookshelves stretched from one wall to the other, each rising nearly to the ceiling. Thousands of scrolls had been arranged according to identification numbers, research categories, and security classifications.
Some scrolls appeared ancient, their surfaces darkened by age. Others were protected by sealed cases or wrapped in preservation cloth.
Tsunade had already memorized the relevant archive code.
"Section C, shelf seventeen," she said. "The original Nerve Activation project should be stored there."
Ren followed her between the shelves.
Even though the archive was underground, not a speck of dust could be seen. Maintenance seals regulated the temperature and humidity, protecting decades of research from decay.
They found the correct shelf without difficulty.
Ren scanned the labels until his gaze settled on a faded scroll wrapped in grey cloth.
Nerve Activation Project—Initial Research Records.
He carefully removed it and carried it to a cold stone table in the center of the archive.
Tsunade remained nearby with her arms crossed.
"You have three days," she reminded him. "Don't rush through the material simply because access is limited. If you misunderstand the principles, this research will be more dangerous than useful."
"I understand."
Ren sat down and opened the scroll.
The first several pages contained a theoretical explanation of the project. Beyond that were anatomical diagrams, chakra-flow models, surgical observations, and tables filled with experimental data.
The language was dense and highly specialized.
Some passages discussed how chakra interacted with neurons and muscle fibers. Others recorded reaction-time measurements before and after stimulation.
Then came the casualty reports.
Subject Four experienced uncontrolled muscle contractions and permanent damage to the spinal nerves.
Subject Seven suffered seizures after the second stage of chakra stimulation.
Subject Nine lost all sensation below the waist.
Subject Twelve entered a coma and never regained consciousness.
The deeper Ren read, the more disturbing the records became.
The original researchers had believed that they could improve reaction speed by forcing chakra through the nervous system. In theory, stronger stimulation would allow messages to travel between the brain and muscles more quickly.
Instead, excessive chakra damaged the neurons responsible for carrying those signals.
Some test subjects became faster for several minutes before collapsing. Others lost control of their own bodies. In the worst cases, damage to the brainstem caused immediate death.
Ren slowed down and reread the experimental sequence.
The project had not failed because its fundamental goal was impossible.
It had failed because the researchers had treated the nervous system like an ordinary chakra pathway.
Meridians could be strengthened through training. Nerve cells were far less forgiving.
Increasing chakra output without accounting for the limits of the cells was like forcing a flood through fragile glass pipes.
Eventually, something would break.
Tsunade stood beside the table, visibly bored but unwilling to leave Ren unsupervised. She occasionally glanced at the scroll, though her expression revealed no desire to revisit the contents.
Ren continued reading.
He was examining a diagram of damaged nerve fibers when he heard something.
It was extremely faint.
A soft, dry sound moved through the corridor outside the archive.
Scrape.
Pause.
Scrape.
It resembled scales sliding across stone.
For a fraction of a second, every hair on the back of Ren's neck stood upright.
The sound stopped outside the doorway.
Then a low, raspy voice drifted into the archive.
"A rare visitor indeed."
Ren's fingers froze against the scroll.
"I never expected you to willingly step inside this place again, Tsunade. Have you finally become nostalgic for our old research days?"
Tsunade turned toward the entrance, her brow tightening.
"It's you."
A tall, pale man stood at the threshold.
He wore the standard green flak jacket of a Konoha jōnin, but there was nothing ordinary about him. His skin appeared almost colorless beneath the dim archive lights, and his long black hair framed a narrow face carrying a faint, unreadable smile.
Most unsettling were his eyes.
Golden irises surrounded vertical pupils that belonged to a serpent rather than a human being.
Orochimaru had appeared.
His reputation alone was enough to silence most shinobi.
He was one of the Legendary Sannin, a student of the Third Hokage, and one of the most dangerous people Konoha had ever produced.
Even without witnessing his strength, Ren felt the threat radiating from him.
Orochimaru had not released any killing intent. He had not reached for a weapon or made a hostile movement.
Yet meeting his gaze felt like discovering a venomous snake coiled beside one's hand.
Ren's body reacted before his mind did. His muscles tightened, and his heartbeat quickened as an instinctive warning spread through him.
Danger.
Do not let this man become interested in you.
Before the team assignments, Ren had briefly considered the possibility of becoming Orochimaru's student.
There was no denying the man's brilliance. Orochimaru possessed extraordinary knowledge of ninjutsu, human anatomy, chakra, seals, bloodlines, and forbidden techniques.
Under his guidance, a talented student could grow at a terrifying speed.
The problem was surviving that guidance.
Orochimaru's curiosity had no moral boundary. Human life was simply another resource he could consume in pursuit of knowledge.
By this point in history, he might already have begun exploring methods to overcome death. Perhaps his research into the Living Corpse Reincarnation had started, and he was quietly evaluating talented shinobi as potential future vessels.
Ren's current abilities might not make him Orochimaru's ideal target.
However, he was talented enough to become a candidate.
Since he already had access to teachers like Minato and Tsunade, there was no reason to place himself within reach of the most dangerous researcher in Konoha.
Ren stood and bowed politely.
"Lord Orochimaru."
Orochimaru's serpentine eyes shifted toward him.
Ren calmly returned to his seat and lowered his gaze to the scroll, making no attempt to continue the conversation.
The less attention he attracted, the better.
Unfortunately, Orochimaru's interest had already been stirred.
His gaze moved past Tsunade and settled on Ren with quiet curiosity.
"This child is unfamiliar," he said. "Is he a new student you've taken?"
"Not at the moment," Tsunade answered coldly.
Orochimaru's smile widened slightly.
"Not at the moment?"
He repeated the phrase as though tasting its meaning.
"How surprising. I assumed grief had extinguished your desire to teach anyone."
Tsunade's expression became dangerously still.
Orochimaru continued in the same soft voice.
"If you're willing to personally bring this child into a restricted archive, he must possess something unusual."
Tsunade did not answer.
She shifted half a step to the side.
The movement appeared casual, but it placed her directly between Orochimaru and Ren.
Ren noticed.
So did Orochimaru.
Silence filled the archive.
After several seconds, Orochimaru stepped inside. His movements were unhurried, but even his footsteps made almost no sound against the stone floor.
He stopped a short distance from the table and glanced at the open scroll.
"The Nerve Activation Project?"
A faint trace of amusement entered his voice.
"That research was abandoned for good reason. Its creators chose the wrong direction from the beginning."
Ren kept his expression neutral.
Orochimaru approached one of the nearby shelves.
"They focused entirely on forcing chakra into nerve fibers," he continued. "They believed that stronger stimulation would inevitably produce faster reactions."
His long, pale fingers moved across several scrolls before stopping on a dark-green one.
"They ignored cellular tolerance, energy-conversion efficiency, and the damage caused by repeatedly disrupting the natural electrochemical process."
Orochimaru removed the scroll.
"Failure was inevitable."
He returned to the table and placed it beside Ren's hand.
This scroll was considerably newer than the first. Its edges had not faded, and the seal binding it remained clean and sharp.
"If the subject interests you, read this instead," Orochimaru said. "It contains research from the past year."
Ren looked at the title.
Controlled Cellular Resonance and Directional Nerve Reinforcement—Second Revision.
"The research is incomplete," Orochimaru continued. "But unlike that discarded project, its underlying direction is correct."
His golden eyes rested on Ren.
"Whether a child at your level can understand it is another question."
Ren did not immediately touch the scroll.
He glanced at Tsunade.
Her expression remained tense, but she did not stop him.
After a moment, Ren untied the binding and spread the dark-green scroll across the table.
The first page contained a diagram of a human nervous system overlaid with a complex chakra network.
The instant Ren began reading, the Gala System reacted.
[Ding! A high-quality potential conquest-target fragment has been detected: Nerve Activation Technique—Incomplete.]
Ren's eyes narrowed.
A fragment?
This was the first time the system had classified a technique that way.
A second notification appeared.
[Would you like to initiate the Encounter? Yes/No]
Ren hesitated.
Neither Tsunade nor Orochimaru seemed focused on the minute changes in his expression. After taking a slow breath, he selected Yes.
The archive vanished.
In its place appeared the interior of a dark underground laboratory.
A large life-support chamber stood at its center, filled with faintly glowing nutrient fluid. Suspended inside was the personification of the incomplete technique.
She appeared young, but her body was unfinished and terribly damaged.
Her skin was deathly pale. Medical cloth covered her torso, while both arms ended at the shoulders and both legs were absent above the knees.
Countless tubes connected her body to the chamber.
Her eyes remained tightly closed.
Her chest did not move.
She could have been sleeping.
She could have been dead.
A dialogue panel appeared before Ren.
[A: Wake up. You're not allowed to sleep here.]
[B: Hello. Can you hear me? My name is Ren. It's a pleasure to meet you.]
[C: Remain silent and observe her condition.]
Ren considered the choices before selecting B.
"Hello. Can you hear me? My name is Ren."
No reaction came from inside the chamber.
The incomplete technique remained motionless.
The dialogue panel appeared again.
Ren chose A.
"Wake up. You're not allowed to sleep here."
Nothing changed.
He selected C and quietly observed her.
Seconds passed.
The fluid inside the chamber remained perfectly still.
"Why doesn't any option work?"
Ren studied the motionless figure.
Was she incapable of responding because the technique itself had not yet been completed?
If that was true, then beginning the Encounter was not enough. He would first need to finish developing the Nerve Activation Technique before its personification could awaken.
The difficulty had just increased enormously.
During this period, techniques such as the Rasengan and Chidori might also exist only as incomplete concepts. Ren had previously wondered how the Gala System would interpret ninjutsu that had not yet been fully developed.
Now he had his answer.
It treated them as broken conquest targets.
They could be found.
They could be approached.
But they could not truly respond until someone made them whole.
"Interesting…"
Ren stared at the silent figure for another moment before dismissing the system scene.
The underground archive returned around him.
Orochimaru's voice immediately entered his ears.
"Well, child? How much of that scroll can you understand?"
Ren looked down at the pages.
"A small portion."
Orochimaru's smile suggested that he did not believe such modesty.
Ren hesitated before speaking.
"The older project treated nerve conduction as though it were no different from moving chakra through the meridians. But nerves transmit information through electrochemical impulses produced by changes in the cell membrane."
Tsunade's attention shifted fully toward him.
Ren continued.
"Forcing chakra into the nerve fibers may temporarily accelerate the response, but the stimulation disrupts ion balance, damages neurons, and reduces their sensitivity. Repeated use would eventually destroy the structures the technique is supposed to enhance."
A faint light appeared in Orochimaru's eyes.
"The newer research takes a different approach. Instead of forcing the nerves to operate faster through external pressure, it attempts to guide the cells into a controlled resonance with chakra."
Ren traced one of the diagrams with his finger.
"If the resonance can be stabilized, the technique might improve signal transmission without tearing apart the nerve fibers."
The archive became silent once more.
Orochimaru looked at Ren as though seeing him for the first time.
Not as Tsunade's young assistant.
Not as an ordinary genin.
As something interesting.
"Oh?"
His smile slowly widened.
"To distinguish the fundamental difference between the two projects after reading only a few pages…you're far more capable than you appear."
Orochimaru leaned slightly closer.
"Then tell me, Ren."
One pale finger tapped the most complicated formula on the scroll.
"How would you capture a cell's resonance frequency—and reinforce it in only the direction you desire?"
Ren stared at the formula.
Answering incorrectly would reveal the limits of his knowledge.
Answering correctly might earn Orochimaru's attention.
And in that underground archive, Ren was no longer certain which outcome was more dangerous.