My Perfect Isekai: Pragmatic Protagonist, Progression Fantasy and Strategy

The midday sun scorched the back of the neck with ruthless, desert-like intensity. The forest training ground, which over the past months had become the entire world for my body and mind, was now enveloped in thick, suffocating dust. Every step, every attempt at a sharp dodge kicked up a cloud of gray dust that settled on my sweaty skin, mixing with blood from a split lip and fresh, sticky sweat. There was not a trace of cool air in the wind—only a dry, stifling heat scented with warm resin, pine needles, and sun-baked grass.

”So what if you sent the signal?” Master raised an eyebrow slightly, looking at me with his clouded, blind eyes. He took a step closer, his stooped silhouette exuding a raw, unshakeable calm. ”You see the storm coming, but your Vessel is still constrained by the structure of a mortal. The signal you speak of must travel from your head, through the spinal cord, all the way to the muscle fibers. To your mind, that’s a fraction of a second. In high-level combat—it is an eternity. Speed isn’t just fast legs, Dave. It is the time that elapses between the thought and the physical contraction. And your biological conduits have their limits that you cannot push simply by swinging a sword or running through the forest. The synaptic response has a physiological wall. You cannot jump over it with ordinary motor training.”

The old man turned his back, letting me know the morning session was over.

”Rest. Your Vessel needs regeneration. But remember: until you shorten the path between impulse and action, you will always be a millisecond behind my staff. And on the deep floors of the dungeon, where monsters don’t rely on human senses, that millisecond difference is the only boundary between living and becoming a shapeless mass of meat and bone.”

I sat down in the deep shadow of a massive basalt block, leaning my back against the comfortably cool stone. I closed my eyes, catching deep breaths that burned my throat. The air around trembled with heat, and Master’s words still echoed in my ears. Every heartbeat felt like a blacksmith’s hammer pounding against my temples.

Biological conduits have their limits... I repeated mentally, analyzing the situation with the cold, mathematical precision that defined my engineering mind.

My energy conduits were now empty, quiet, and cold. Following the old man’s teachings, I wasn’t pushing mana through them, allowing my body its natural, physical recovery. However, my mind—that cold, logical calculator that always broke down mysticism and magic into basic components—went into overdrive, ignoring the fatigue.

Knowledge from my previous life, spanning physiology, neurology, and physics, combined with the unique mechanics of my sapphire lightning, began to assemble into a coherent, if terrifyingly dangerous, framework.

A normal nerve impulse in a human travels at roughly one hundred meters per second, I calculated coldly, running my fingers slowly over my sore, tense thigh. That is the biological limit of the human race. A mortal Vessel, even reinforced by an Astral Core, still relies on the same organic infrastructure. The impulse has to jump across synapses, release neurotransmitters, activate acetylcholine receptors... It takes time. Even with peak reflexes, the delay is several dozen milliseconds. But I am not an ordinary mortal. My innate magic is sapphire lightning. Electrical current that travels through metal wires at speeds approaching the speed of light.

I slapped my palm against my knee until the dull sound echoed across the quiet training clearing.

Conduits are wires. Pipes and copper cables through which my energy flows. If I can control lightning magic externally, why the hell shouldn’t I control it inside my own system? What would happen if, instead of waiting for a slow, biological nerve impulse to travel from the brain to the muscles, I shortened that path to zero? What if I used a micro-electrical discharge channeled directly through my cold conduits to the motor fibers, bypassing the entire nervous system?

It was a brilliant, yet lethal theory. I wasn’t talking about a constant body enhancement—attempting to run continuous current through muscles would instantly cook them, char the nerves, and stop the heart. Electricity is a destructive force that ruins delicate cellular structure.

This was meant to be something entirely different. A single, clinical short-circuit. Sapphire Spark (Mgnienie Szafiru).

A single millisecond spark, I thought, my eye gleaming with cold, analytical fervor. A single micro-spark delivered directly to the motor node in the thigh or arm. A controlled short-circuit that triggers an immediate, involuntary muscle contraction. Bypassing biological reflex. Movement faster than physiology allows. If I can control the vector of a lightning strike, I can force the contraction of a specific bundle of muscle fibers.

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I had to test it. And I had to do it in absolute secrecy from Master, who would undoubtedly consider it pure madness.

Late in the afternoon, when Master headed into the woods to gather thick branches for the evening fire, I stood up slowly. My heart beat steadily, but adrenaline coursed through my veins. I stood in the middle of the empty training ground, looking at one of the basalt pillars I had erected myself.

I relaxed my entire body. My conduits were quiet, empty, and cold—just as the old man had taught me during the lessons in the craft of disorder. No tension, no energy flow.

”Alright,” I whispered to myself, focusing my entire will on a small, specific point in my right thigh. ”Just one spark. The smallest I can conjure. A minimal short-circuit in the primary motor channel of the quadriceps.”

I closed my eyes. I visualized my conduits as empty copper pipes. In the branch running directly to the quadriceps muscle, I formed a tiny sapphire charge. I didn’t use roaring, external magic for this—it was pure internal manipulation of micro-particles of energy. The precision of a smith placing the finest pattern on steel.

And I released the spark.

HISS!

The effect was instant and agonizing.

Instead of a smooth, rapid contraction, my thoughts and calculations slammed into brutal biological reality. The voltage was too high, and the charge was too chaotic. The sapphire spark struck the bundle of muscle fibers like a miniature bolt of lightning. The quadriceps of my right thigh contorted in a horrific, paralyzing spasm. The muscle hardened to the density of steel, and a searing, tearing pain exploded in my leg as if a white-hot iron rod had been driven straight into my thigh!

”Aaargh!” A scream tore from my throat before I could stifle it.

My right knee buckled helplessly, and I slammed hard onto the unyielding ground of the training field, my face plowing into the gray dust. My right leg quivered in gruesome convulsions, the muscle bundles under the skin twisting into hard, painful knots, while the energy conduits around the thigh erupted with hot, acrid vapors of burned ether.

From the dense brush, Master landed right beside me. He dropped the gathered branches onto the dirt, his clouded eyes scanning my battered leg with cold yet deep concern.

I tried to answer, opening my mouth, but the pain in my thigh produced only a quiet, choked groan. My body shuddered in spasms.

Master leaned down without a word, taking my leg into his rough, stone-hard hands, and with brutal, surgical force pressed down on one of the Inertia Block points directly behind my knee. A dull, wet pop echoed, the spasm in my thigh instantly released, and I collapsed limply to the dirt, gasping greedily for air.

”Your Astral Core is still too weak,” Master continued, looking down at me with deadly, stern gravity. There was no anger in his clouded eyes, only deep artisan concern mixed with rigor. ”Your conduits are like thin spider threads, and you are trying to force a river of liquid fire through them. If you do this again, your own muscles will tear from the bone, and your conduits will burn to ash, leaving you a useless cripple for the rest of your life. You will destroy an infrastructure that would take decades to rebuild. I forbid you from touching this until your Vessel reaches the Monolith phase! Do you understand me, kid? This is not playing at blacksmithing where you can re-melt a broken sword. You cannot re-melt the soul and ruined conduits.”

Still trembling with pain and drenched in cold sweat, I slowly nodded, clenching my fists.

”I understand, Master,” I rasped harshly, feeling sensation slowly return to my leg with a painful tingling.

”Good. Get back to the shelter and let healing salve be rubbed into that leg. Tomorrow morning we start staff sparring anew. And woe to you if I detect even a spark of that burned ether in your conduits. The punishment will be carrying basalt for three days straight without sleep.”

Evening brought the long-awaited, frosty quiet. The fire from the small stone hearth crackled softly, casting long, predatory shadows on the tree trunks surrounding the training ground. I sat on a wooden log, slowly and methodically massaging my sore, still slightly twitching thigh. The skin there was reddened, hot, and throbbing, and deep within the muscle a dull, burning ache lingered with every firm press.

He forbade me from using it... and he’s right, I analyzed in the silence of the night, as that characteristic, arrogant, and predatory smile returned to my lips. My body at this stage isn’t ready for a full fusion of lightning magic and motor function. The short-circuit was too strong because the charge was too chaotic and the voltage too high. I treated the muscle like a thick cable, whereas I need to approach this with surgical, microscopic precision. Lower the voltage by ninety percent. Isolate individual muscle fibers, dose micro-amperes instead of flooding the entire thigh with current. I must create fuses within my conduits.

I knew I couldn’t use this technique during sparring sessions with Master. The old man would instantly catch the scent of ozone, and his superhuman energy perception would detect even the smallest short-circuit in my conduits.

This was to be my deepest, most guarded secret. A forbidden, unrefined prototype that I would quietly, millimeter by millimeter, work on in absolute secrecy during solitary, frosty evenings on the training field while the old man slept. I would dose micro-impulses, accustom my conduits to the pain, build tissue tolerance, and learn to control this sapphire spark so as not to destroy my own body, but merely to stimulate reflex.

Sapphire Spark (Mgnienie Szafiru) was meant to remain hidden from the world, concealed from the eyes of the guard, the guilds, and even my own Crew. An unfinished, lethally dangerous weapon that I would reach for only when the day of the ultimate trial arrived. The day my red line was crossed, and I had to become a monster to protect those I love.

I closed my eyes, listening to the crackling fire and the distant murmur of the wind carrying the scent of Crossgard.

The grind continued. But with every passing day, every burned conduit, and every conquered pain, I was laying the foundation for a power that would shatter this entire system. Readers, enemies, and even the gods had no idea what was slowly being born in this quiet, misty wilderness under the eye of the blind Master.