With a tired sigh, I opened my eyes. Sitting on one of the fūin circles in a huge, dimmed-out room, I got up and swept my gaze over the two dozen clones sitting in the same kind of circles—then headed for the big vertical glass chamber in a stone frame at the center of the array.
One step—and the clones dispersed into chakra, getting sucked back into me. A couple more, and the chamber, hissing out steam, clicked open, revealing a naked man.
Clean skin—like some model who lives on the most expensive creams. Defined muscles, those aesthetic ripples that could give even Apollo a complex. And silky black hair falling over a face with damn-near perfect features… except for those tiny little tells that still let you recognize the guy who'd been transformed into this walking embodiment of pretty. Even the "two hundred seventy-three" kanji carved into his forehead didn't ruin the picture anymore—healed up on its own, not a trace left.
"Still can't believe something this good can come out of such ugly freaks," I thought, looking over the next test subject.
That was another thing I'd built into my body-enhancement project: appearance changes. Not even close to the biggest achievement, by the way. What mattered way more was—
The subject's eyes slowly opened, focusing on me. Then, the next instant, they bulged wide.
"Nooooo!!!" he screamed, recognizing me. His limbs instantly started moving, trying to get out of the chamber, but all he managed was one awkward flail—and then he just ate the floor. "No… no… no… just not again…"
He tried to crawl, but his limbs—so powerful now, but brand-new—still didn't have the neuromuscular connection trained in. So all he could do was this clumsy, splayed-out scrambling with hands and feet.
"I haven't run the painful experiments on you yet. For now," I said, walking up. Then I just lifted the thrashing body by the neck and dragged him deeper into the lab, toward another room.
The subject kept screaming and trying to break free—and in barely ten seconds he got a handle on his new limbs enough to land a couple heavy hits on me, the blows echoing with a dull, meaty thud.
"Hmph." That was all I gave him before I pushed my chakra through my arm almost unhindered, dropping him into unconsciousness with genjutsu. "Genin-level strength, with chakra-reinforced strikes, in a worthless nobody like this. Yeah. That's science shitting on talent and hard work."
Soon we reached the destination, and the subject was strapped into the fūin analyzer.
This was the finale of the project. And it wasn't the first today—wasn't even the tenth overall—where I once again confirmed my calculations were dead-on.
I could calculate a whole damn lot. Not everything, though. The first three corpses from this stage of the body-enhancement project would confirm that. But together they gave me enough data that the numbers for my own body came out insanely close to "perfect." Close enough that if something did go wrong, odds were even higher I could patch it up afterward.
In a few days, once I stockpiled more clones with full chakra reserves, I'd perform the essence of the project—an EX-rank technique—on myself.
May 1st. Rebirth Day. Third-person POV
In the center of the biggest hall in the laboratory stood a horizontal chamber—like a coffin of cloudy white crystal. The analyzer's metal framework hung over it. And all around—on the floor, the walls, even the ceiling—insanely complex fūin circles and schematics pulsed, weaving into one living network. Twenty stable shadow clones sat at the key nodes of that network, ready to do their work with jeweler-level precision. These fūin were "crutches," necessary for a procedure that even their original's already-boosted control still couldn't pull off solo. Sure, the recent rise in sensitivity and control from the soul's growth let him add a few more strokes to the final calculations, making the technique a bit stronger than planned—but it still didn't let the one whose body slept in the sarcophagus cheap out on the number of clones.
That web of interlaced fūin… was the most perfect, most complex thing this world had ever seen.
The moment their creator sank into complete unconsciousness, without hesitation, the clones got to work.
Each formed a different series of hand seals, and the fūin symbols in the room started to come alive right before the eyes, sliding around in seemingly chaotic motion. Then, with one unified smack of their hands against the floor, part of the fūin "flowed" onto the sarcophagus, wrapping it and lighting up white.
The body's reconstruction had several stages. The first had just begun.
First, chakra streams guided by the clones began rebuilding the body's frame. Fūin analyzers linked to the chamber transmitted every tiniest transformation into the clones' minds, each change obeying the new will forced onto it.
The procedure started with the skeletal system. Chakra stimulated an insane densification of bone tissue, altering its crystalline structure and making it 30–40 times stronger than normal. At the same time, natural growth was preserved—important, so the original wouldn't end up stuck in a kid's body later. Bone marrow underwent deep modification, starting production of a new type of blood cell more tightly tied to chakra, able to carry energy more efficiently.
In parallel, the muscular system was rebuilt. It was surgery at the cellular level. Muscle stem-cell growth was stimulated, and they began forming new fibers. 90% of the muscles were repurposed into "power" and "burst" types, their density increasing 50–60 times. The key point was this: the old, even if effective, mitochondria were replaced by new, more functional "chakra energy generators." Basically mitochondria, just feeding directly on chakra—able to work indefinitely without needing oxygen or glucose. Now the muscles could work indefinitely on chakra; though at the peak of their capabilities—about three minutes—they were designed to dump colossal, inhuman strength on the back of equally inhuman energy reserves, in short but destructive bursts.
At the same time as bones and muscles, tendons and ligaments were rebuilt too. Their strength increased 110-fold. Elasticity hit a level unreachable by normal methods—they could handle the loads of the enhanced muscles and wouldn't tear. An extra layer of collagen and fiber flexibility gave insane mobility; braided through with thin chakra channels, they guaranteed flawless linkage with the new muscular system.
Inside the crystal chamber, waves rolled under Naruto's skin. For a moment, his body lit up from the inside with a mesh of new, shining channels—not just the original Chakra Circulation System, but thousands of new microscopic paths being built in real time, threading through every cell.
After several hours of work, the stage was completed. The fūin wrapping the chamber vanished, and after a few seconds' pause the clones again formed different combinations of seals in unison and slammed their hands to the floor. All so the second portion of the room's fūin could "crawl" onto the chamber and flare to life.
The clones' focus shifted. Now they worked on the systems meant to feed and control this new, stronger "engine"—the parts of the body that had just been reinforced.
The cardiovascular and respiratory systems were rebuilt in sync. The heart transformed into a powerful "chakra pump," able to circulate chakra-enriched blood through the body with ridiculous efficiency. Vessels were strengthened to withstand higher pressure, and the capillary network expanded threefold, giving unprecedented nourishment to every single cell. The lungs were kept, but reoriented: their volume and alveolar surface area increased significantly, and the endurance of the breathing muscles—like all the body's muscles—rose. Now they could function without air indefinitely, always filling with the owner's chakra to spread it in high concentration throughout the body. Chakra could already nourish the organism well, but with these changes the cost would become far more targeted. That meant lower chakra expenditure, bigger results with fewer losses—or, at rest, much lower energy consumption.
Then the clones moved on to the subtlest and most complex stage: the nervous system and brain. This demanded absolute, surgical precision. The myelin sheaths thickened and were replaced with new, more chakra-conductive channels, boosting signal transmission speed 20-fold. Synapses were optimized for instant reaction. In parallel, the brain was rebuilt: the neuron count increased tenfold (significantly higher than in any test subject, thanks to feeding off Naruto's colossal chakra reserves), and connectivity between them was strengthened. The sections responsible for chakra control were reinforced the most. That led to an exponential rise in computing power, learning, and analysis—to an unprecedented level. A micro-construct of "combat adrenaline" was also embedded into the brain: a reflex program for auto-acceleration in danger, switchable on consciously.
The fūin analyzers transmitted into the mind—like pictures on a display—the moment they recorded an unbelievable, blinding spike of neural activity. The map of the nervous system literally "lit up" with light.
A long time passed before that stage ended too. The clones repeated their floor-smack ritual, and new fūin flared across the chamber.
The clones moved on to the systems meant to push the body to a completely new level of existence, making it semi-autonomous and hypersensitive.
The digestive and endocrine systems were radically altered. The digestive system was preserved as a backup, but now it was optional. The body was fully rebuilt to feed on chakra. It could process any organic matter into pure energy, utilizing food with almost no loss (99.9% assimilation efficiency). The endocrine system was placed under full conscious control, allowing deliberate hormone control, switching off pain, and regulating emotional states as needed.
The immune system and regeneration became the apex of all transformations. The Hayflick limit was disabled at the genetic level—cells no longer aged naturally. DNA gained repair mechanisms and anti-cancer safeguards capable of instantly neutralizing pathogens and restoring damage. Antioxidant enzyme levels increased. Instant healing of minor wounds became automatic, requiring no conscious control. Limb regeneration took hours if the body was unconscious, and minutes if conscious and under the reborn one's control. Recovery from critical damage took minutes. More than that: based on the pattern found in chakra—so-called "affinity," which exists in all shinobi—a construct was built inside the body that enabled this regeneration. Simply put, all templates were inside it now, and chakra had something to follow even without conscious effort. And on top of that, it boosted regeneration so much the body could survive even decapitation—the head would be restored from the template and the soul's memory. Though that would require conscious assistance from the soul, so realistically only Naruto could pull that off.
The senses underwent final calibration. The number of photoreceptors in the eyes increased, allowing much sharper vision. Hearing expanded from infrasound to ultrasound. Smell became capable of deeper analysis of scents, and touch became inhumanly fine. The ability to "dampen" sensitivity improved to avoid overload from the new sensations. Though, considering the brain's increased capacity, that last part was really just a secondary measure.
Again: hours of work, the end of a stage, and a transition to the next.
The final—and most important—stage: rebuilding the Chakra Circulation System itself. Using all data gathered from Asura's and Indra's constructs, a long-term reconstruction of the CCS began according to a new, "ultimate" template.
New growth zones were introduced into the CCS. A process of balancing Yin and Yang was launched—something that had been skewed since birth. A new growth vector was set: for now and the near future, doubling the reserve every three months with intensive training (and enough chakra to "feed" that growth, a big chunk of it coming from the Kyūbi). Chakra density would increase too.
In short, the body was rebuilt on a far more perfect template (with the CCS only on its earliest foundations) than even Asura's or Indra's. It became the strongest foundation—the highest step of evolution.
The procedure was finished. The fūin on the floor, walls, and ceiling went dark, their glow slowly fading. Only the node points remained unchanged. The clones, drained—almost all their energy spent building new parts of the CCS inside the original's body—dispersed into chakra and returned to him.
The sarcophagus clicked open, releasing a cloud of cold steam. Inside, under a soft hiss, lay a body that was both familiar—and completely alien.
The first thing I felt was silence. Not the room's quiet, but internal silence. There was no familiar background noise of a working body—no heartbeat, no breathing, no stomach rumbling. There was only the steady, powerful, soundless pulse of chakra, rolling through my body in waves.
The world crashed into me in an avalanche of sensation. I saw dust motes inside the chamber, dancing in the beams from the lamps piercing through the glass's semi-transparent surface—and with a clarity that used to be a pain in the ass to achieve even with chakra. I heard the hum of power cables deep beneath the lab floor, and the beat of a moth's wings outside, beyond the thick walls. My sense of smell separated ozone from working seals, the scent of metal, and the cold, sterile aroma of medical solutions from other rooms. And my brain—rebuilt and ramped up—processed that flood of data without the slightest strain.
Sensations I used to get only by using techniques and concentrating chakra were now just my default state. And they were ready to shoot way higher if I used chakra consciously.
The sarcophagus opened, releasing a cloud of cold steam. Awkwardly lifting my hands, I barely managed to hook my fingers over the edges to sit up… and heard the chamber crack from that simple motion. The body was light—insanely light—yet at the same time packed with monstrous, spring-loaded strength. But. It still hadn't learned how to use that strength.
Letting chakra threads slip out of my fingers—easier than ever—I used them like tentacles to lift myself and set my feet on the floor.
The threads slowly transferred the weight from themselves onto my limbs, and I felt it clearly: the solid floor under me just caved in. After the upgrade, my body should've weighed a little over a ton and a half—about thirty times more than before.
Yeah… If scientists from my old Earth found out what and how I did to my body, they'd call me a heretic and burn me at the stake. What I did here would be, I guess, very unscientific over there. But this world has its own rules.
My legs moved wrong. My brain gave a small command—"stand up"—calculated for old, weak muscles and slow nerves. The new body responded with such speed and power I almost lost my balance. The neuromuscular connection was snapped, basically near zero compared to what it used to be.
Almost falling, I took a step. Clumsy, shaky—like I'd decided to get wasted for the first time in my life. Second step—more confident. Third—even steadier. With every movement, every muscle contraction, I felt my new brain rewriting old reflexes at a crazy pace, calibrating itself to the capabilities of a perfect shell.
Chakra moved through my legs, effortlessly spreading my weight over a larger area so the floor wouldn't buckle.
After ten steps, my gait went from crooked and inaccurate to even. After twenty—into something absolutely silent, smooth, and predatory, like a panther going out to hunt.
Reaching the doors leading out, I smoothly pressed my fingertips to the nearby panel, and after a pulse of chakra the fittings unlocked. Watching that, I clenched my fist. Then my gaze dropped lower, to muscles so even and aesthetic it was almost stupid.
"Perfect~" I whispered, and my voice—no longer needing breath, produced through naturally generated Wind-nature chakra—came out especially even and clean. "But I need a test…"
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