The first thing I realized was that the human eye is a remarkably flawed piece of hardware. It has a blind spot where the optic nerve passes through the optic disc. It suffers from saccadic masking—the brain literally shuts off visual processing while the eye is moving so you don't see a motion blur.
In my old life, I was a data analyst with a hobby for "technical" gaming. I liked systems. I liked knowing how the clock worked.
In this life, those flaws were going to get me killed.
I opened my eyes to a world of grey mist and the smell of ozone. I was small. My hands were tiny, the skin stained with soot and the copper-tang of dried blood. I was lying in a trench. Above me, the sky was a bruised purple, choked by the smoke of a Great Fireball Technique that had recently scorched the earth.
"Kaito! Get up! They're through the perimeter!"
The voice was shrill, panicked. I turned my head. A boy—no older than nine—was clutching a short-sword with trembling hands. His Uchiha crest was torn, the white fan stained black by ash.
I didn't answer him. I couldn't. My brain was busy recalibrating. There was a foreign energy—chakra—circulating through my nervous system like liquid mercury. It felt cold. It felt logical.
I pushed myself up. My muscles burned with lactic acid. I did a quick inventory.
* Weaponry: Three kunai. One wire spool (high-tension steel). Four explosive tags (standard grade).
* Condition: Dehydrated. Mild concussion. Fractured left rib.
* Surroundings: A bottlenecked canyon. Three Senju signatures approaching from the North-East.
The boy, whose name my new memories identified as Taiga, was hyperventilating. "We have to run, Kaito! The Hagoromo scouts said the Senju brought a Water Style specialist!"
I looked at the canyon walls. They were limestone—porous, high in calcium carbonate.
"Running is a low-probability survival strategy, Taiga," I said. My voice sounded alien—monotone, detached. Nathaniel Gwyn would have been proud. "Their movement speed is roughly 1.4 times ours. We'd be caught in the open within sixty seconds. The sensorimotor gap between their detection and our execution is our only win condition."
Taiga stared at me like I was speaking gibberish. "What?"
"Stay behind me. Don't breathe too loud. It interferes with my acoustic tracking."
I stepped out of the trench. The first Senju appeared. He didn't look like a ninja from a manga; he looked like a butcher. He wore heavy iron plating over a blue kimono. He moved with a heavy, grounded gait—a specialist in Earth or Water.
Technical Assessment: The enemy's weight distribution suggests a center of gravity shifted forward. He's confident. He's relying on his armor.
I didn't use a jutsu. I didn't have the reserves. Instead, I grabbed a handful of fine limestone dust from the trench floor and mixed it with a drop of water from my canteen.
As the Senju lunged, his blade whistling through the air with a frequency of about 440Hz, I didn't dodge. I stepped into his guard.
"Foolish brat!" he spat.
He swung. I dropped.
The physics were simple. A long-sword has a minimum effective range. By closing the distance to less than six inches, I entered his "Dead Zone." I slammed the wet limestone paste into the joints of his neck armor. At the same time, I kicked the back of his knee.
The human knee is a hinge joint. It is not designed to withstand lateral force while bearing 200 pounds of armored weight.
Crr-ack.
He went down. As he fell, I pulled the wire spool. I didn't aim for his neck. I aimed for his eyes.
The Sharingan in my right eye flickered to life. It didn't feel like a power-up. It felt like someone had overclocked my processor. The world slowed. I could see the individual droplets of sweat flying off his brow. I saw the lag in his pupils as they tried to track the wire.
I looped the wire around his helmet's visor and yanked. The high-tension steel sliced through the leather straps, pulling the heavy iron plate directly into his orbital sockets.
He didn't scream. He made a sound like a wet sponge being stepped on.
"One," I whispered.
I didn't feel remorse. I felt a strange, clinical satisfaction. The "Game" was different here, the stakes were higher, but the rules of physics still applied. If I could map the technical vulnerabilities of this world, I wouldn't just survive.
I would dismantle it.
Technical Note: The Senju's death took 4.2 seconds.
Efficiency could be improved by 15% if I used the explosive tag as a distraction rather than a finisher.
I looked back at Taiga. He was frozen.
"Two more coming," I said, wiping the limestone dust from my hands. "Taiga, give me your explosive tags. I need to calculate the structural integrity of that overhang."
I wasn't a hero. I wasn't even an Uchiha, really. I was a man who saw the world as a series of technical errors. And I was going to fix them.