My Perfect Isekai: Pragmatic Protagonist, Progression Fantasy and Strategy

The basalt ceiling cracked with a hollow, powerful roar that struck directly into the eardrums, causing a painful resonance within the skull. The first wave of thick, biting dust hit Dave directly in the face, but the boy didn’t even blink. He stood firmly on his feet, his bare soles spread wide on the rough stone, while a brazen smile slowly crept onto his bloodied lips. He adjusted the waistband of his boxing shorts with a slow, lazy movement, completely ignoring the low, murderous vibrations that traveled through the arena plate and echoed across the entire chamber. The mountain was claiming its due, and the cracked, raw cave of Yomi II was slowly turning into a deadly trap with each passing second.

This was not the work of an ancient curse, a dungeon anomaly, or some sudden, illogical eruption of hostile mana. It was raw, relentless physics at work, the laws of which Dave respected above all else. For the past three hours, the boy and the Sensei had pounded each other in this confined space without a shred of mercy, testing the limits of their physical Vessels. Massive, destructive stomps, erratic footwork, sapphire plasma shooting from the boy’s feet during sudden turns, and the heavy, hard impacts of his Gōtai armoring clashing against the bamboo staff with the force of solid steel had finally shattered the chamber’s supporting structure. The basalt pillars, weakened over centuries by moisture, tectonic stress, and time, simply could not withstand such overloads and began to snap like dry tinder.

”This cave is about to collapse, kid!” the old man rasped, retreating against a trembling wall and tightening his wiry hands around his worn bamboo staff. ”We must run! The return path is about to be completely buried under tons of rock!”

”Run, Sensei?” Dave raised a right eyebrow slightly, a predatory, deep flame of joyful excitement flashing in his sapphire eye. ”But we just finished our warm-up. It would be foolish to waste such a perfect, completely free testing ground. Why run when the mountain itself has laid out our next stage of grueling grind?”

Before the old man could reply to such insolence, the ceiling above their heads groaned deeply, warningly. The first multi-ton block of black basalt tore free from the ceiling and plummeted with terrifying, gravitational speed, smashing against the stone plate barely a meter from Dave’s bare foot. The displaced air struck the boy’s face with the force of a minor hurricane, carrying small stone shards that grazed his cheek, leaving a thin, bleeding line. Dave didn’t even flinch. His brain, completely free from human fear or panic, instantly went into a state of cold, engineering calculation. Where the old man saw mortal peril and the chaos of cataclysm, Dave saw an optimal environment to test the limits of his newly calibrated radar.

He activated Yomi II.

Dave completely cut off his physical sight, letting his eyelids fall without a single tremor. An impulse of KAI sent directly from his soul—a silent, high-frequency spherical scanner—spread through the entire chamber in a fraction of a second. To an outside observer, there was no gust of wind, no air wave, no visual flash, but in Dave’s mind, reality underwent an immediate, drastic transformation.

The dark cave lost its biological darkness. The entire surroundings turned in his head into a dark gray, high-contrast three-dimensional model, resembling an advanced geometric blueprint. The walls, floor, and ceiling formed a precise, 3D grid of basalt joints, where every crack and fissure glowed with a faint, blue light. Dave filtered out all unnecessary noise in his perception—the swirling dust, the humid air, and the small, harmless stone shards were completely erased by his mind to avoid overloading his hyperactive processor with useless data.

Instead, the radar sharpened and highlighted key threats. The cracking basalt, which was just beginning to lose its stability under the force of gravity and tear away from the ceiling, lit up in his vision as a bright, sharp silhouette with high contrast. Dave saw the mass of each boulder, the direction of its momentum, and the exact point of impact on the platform before the stone could even gain speed in the air. In this monochromatic scheme, the Sensei was rendered as a dense, highly saturated figure the color of a warm, burning tiger’s eye, and every tiny movement of his shoulders, tension in his tendons, or transfer of body weight was visible to Dave with absolute, machine-like accuracy.

The boy processed this entire image from a third-person perspective (TPP). His mind rendered a tactical board from a camera suspended right above the battlefield, allowing him to see himself, the falling rocks, and the old man as three-dimensional pieces in a logical game of survival. It was a perfect translation of the gaming mechanics from his past life into the raw, physical laws of this world.

”If you want to die under these ruins so badly, I won’t stop you, kid!” the Sensei suddenly roared, his silhouette in Dave’s TPP vision moving forward aggressively, bypassing a falling shard. ”But if you can’t parry my blows while the ceiling is collapsing on your head, your whole KAI is worthless! No one will give you the luxury of stable ground on a real battlefield!”

The old man’s bamboo staff sliced through the air with a savage, whistling speed, aiming directly at the boy’s temple, right beneath a boulder falling from above.

Dave did not use magic. He didn’t fire sapphire lightning or try to shield himself with a telekinetic barrier. Instead, he lowered his stance, bending his knees, and smoothly transitioned into the Lynx Footwork.

His dodges became a fluid, yet completely chaotic, rhythm-less dance. Dave moved low, close to the ground, reacting directly to sudden nerve impulses and micro-vibrations in his body triggered by his ADHD. The Lynx Footwork was asymmetrical, full of unexpected stops, violent hip twists, and lateral leaps that completely shattered the classical rhythm of combat, making him elusive to the opponent’s senses. Dave flowed around the old man’s whistling staff, letting the bamboo pass millimeters from his skin while the world collapsed around them.

In a fraction of a second, his radar registered a massive threat. A cracked, three-hundred-kilogram basalt block was hurtling straight at his back, cutting off his path of escape from the Sensei’s oncoming strike. Dave did not turn his head. A pure calculation of the trajectory in a split second suggested the optimal solution. Instead of tensing his muscles, he completely relaxed his left hip and took a short, sharp step back, letting the boulder fly right past his left shoulder. The stone struck the arena plate with a deafening crash, the rush of wind tugging at Dave’s coat. The boy immediately used the boulder as physical cover, blocking the old man’s line of attack for a brief moment.

”Too slow, kid! Do you think a standing rock will save you?” the Sensei’s voice rang out right above his ear as the old master leaped over the falling rubble with inhuman agility, his bamboo staff shifting its vector and cutting toward his ribs from the side.

Dave tried to slip under the sweep, but a sharp stone shard falling from above forced him into a sudden, unnatural position adjustment to the left. He lost a precious fraction of a second, a fraction that decided everything in combat at this level. The old man’s staff struck his right shoulder hard, tearing the skin and sending a spray of blood onto the rough, dust-covered basalt.

Pain exploded in Dave’s shoulder in a hot wave, but the boy didn’t even hiss. His expression remained completely indifferent. In accordance with the principle of controlled masochism deeply embedded in his Vessel, the boy treated the pain strictly as a raw, dry information signal. Pain was not a cause for panic or weakness—it was simply another variable in the equation, a physical feedback signal about an error in positioning and timing that his brain immediately analyzed, drawing conclusions and correcting his movements on the fly.

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He did not maintain his Gōtai armoring continuously. Constantly keeping a hard, condensed layer of will around his body would choke his energy splotches, consume massive amounts of mana, and most importantly—slow down his movements, stripping him of flexibility. Under a collapsing ceiling, a rigid armor would mean certain death beneath the tonnage of rocks. Instead, Dave applied the interval, phase-shifting of power that he had developed based on an engineering approach to energy flow.

Another gargantuan boulder, the size of an entire transport wagon, tore free directly above him, carrying momentum that threatened to crush his Vessel. Dave had no room to dodge—he was cut off by the old man’s bamboo staff on the left, and a pile of already broken, sharp rocks on the right. The boy clenched his teeth, his sapphire eye flashing with a cold light.

In a fraction of a second, at the exact millisecond of the basalt’s contact with his body, his splotches flared with sapphire. Dave pumped condensed KAI directly into his left elbow and forearm, turning them into an inviolable, solid Gōtai monolith with the density of diamond.

BUM!

A massive kinetic implosion followed, shaking the entire chamber. The multi-ton boulder exploded instantly upon colliding with his hard forearm, shattering into hundreds of tiny shards and gray dust that covered the arena. In the exact same millisecond that the impact force was neutralized, Dave completely extinguished the armor, relaxing his splotches to zero. This instant decompression allowed him to maintain his full, inhuman agility and, with a fluid twist of his spine, slip effortlessly beneath another murderous thrust of the Sensei’s staff aimed straight at his exposed throat.

It was pure, ruthless combat engineering, with no room for unnecessary movements or emotions. Dave parried, dodged, and shattered obstacles in a perfect, erratic rhythm, completely controlling his resources. The falling boulders were no longer a deadly threat—they became elements of the battlefield’s tactical geometry. He used them as cover against the old man’s attacks, blocked his trajectories, and forced the master to constantly shift positions, while the Lynx Footwork allowed him to circle the opponent silently, chaotically, and unpredictably.

The tremors of the mountain slowly began to weaken, transitioning into low, sparse rumbles. The last large blocks of basalt tumbled with a loud crash into the deep crevices at the edges of the chamber, and the heavy dust began to slowly settle, covering the entire room in a thick, gray layer like winter snow.

The cave of Yomi II was completely demolished. The monumental walls were heavily cracked, the ceiling had lowered by several meters, and the old, familiar corridors had ceased to exist, buried under tons of rock. Only the solid, basalt arena plate in the very middle survived, along with a small, weakly flickering campfire in the corner that had somehow escaped being buried under the collapsing walls.

Dave slowly opened his eyes, deactivating the three-dimensional radar in his head. The sapphire glow in his pupils slowly faded, giving way to its deep, natural color. The boy stood in the middle of the ruins with a brazen ease, keeping his hands deep in his pockets and shaking the basalt dust from his black coat with a single quick shrug of his shoulders. His splotches in his chest purred stably, and his Vessel, despite the exhaustion, quickly regenerated micro-tears in the tissue thanks to the high density of its fibers.

The Sensei lowered his bamboo staff, leaning on it heavily and breathing loudly. The old master had a face smudged with soot and dust, and his misty tiger’s-eye eyes looked at Dave with a devout, deep, and completely silent respect. The old man, in all his long, grueling life, had never seen anyone who could combine such an erratic chaos of movement with surgical, machine-like precision under the pressure of a collapsing mountain.

”I consider the radar and dodging training officially completed, Sensei,” Dave said with a brazen ease, crouching by the surviving campfire without any haste.

He grabbed a clay cup that had somehow survived the cataclysm and poured the rest of the steaming, bitter herbal infusion from the clay kettle sitting on the edge of the hearth. He drank it slowly, feeling the high temperature of the liquid stabilize his energy splotches and soothe the micro-tears in his tissues. Yomi II, the Lynx Footwork, and the interval Gōtai had ceased to be artificial techniques he had to remember during a clash. They had been 100% integrated into his biology, splotches, and nervous system. They became his new reflex, a part of his physical Hardware.

The boy smiled slightly, confident in his newly acquired power. He was convinced that with such mobility, a flawless radar, and a dynamic defense, no one in the divided city of Crossgard would be able to even touch him, and clearing the dungeons there would be just a matter of time and proper optimization.

The old man walked over slowly, limping slightly on his left leg, and looked down at him. There was no admiration or pride in his Tiger Eyes, however. A freezing, predatory, and murderously professional cold of a master who sees a fundamental flaw in the design of his greatest creation appeared there.

”The Lynx Footwork and the Gōtai armoring protect your skin, kid,” the old man said, his rough, low voice cutting through the hollow silence of the demolished cave like a sculptor’s sharp scalpel. ”But answer me one simple question. How do you plan to kill?”

Dave slowly raised his eyes, holding the warm cup in his hand. The brazen ease on his face tensed slightly, his sapphire eye narrowing in anticipation.

”On common sense, Sensei. My fists have enough mass, density, and kinetic force to obliterate any opponent. If I add the condensed sapphire plasma, the enemy will simply explode from within. It’s pure math and physics,” Dave replied calmly.

”You swing those arms like a strong, mindless butcher at a market, relying solely on the hope that the enemy will break under the sheer force and tonnage of your blows,” the old man spat ostentatiously on the crushed basalt lying between their feet. ”That is not craftsmanship; it is the clumsy butchery of an amateur. What will you do when you face an opponent who can flow with your strike? Someone who will bypass your kinetic battering ram, slightly redirect the force vector, and use your own momentum to effortlessly snap your neck? Will you just swing your fists blindly, wasting precious splotches, oxygen, and Vessel energy on empty strikes?”

The old man raised his bamboo staff and, with a single fluid movement, touched Dave’s chest, right beneath his left collarbone.

”One short press on the brachial plexus,” the Sensei said quietly, and Dave felt his entire left arm instantly go limp, losing all muscle tension as if it had been severed from his body. ”No force used, no wasting of mana. One precise touch, and your left flank ceases to exist. Your weapon slips from your hand, and you become a helpless sack of meat. This is the economy of combat, kid. The body of every mortal, monster, or mage is just a machine. And every machine has its fuses and weak construction points. Instead of smashing thick armor with a hammer, you only need to pull one small pin to make the entire structure collapse into dust.”

Dave narrowed his sapphire eye, and a new, incredibly complex tactical calculation immediately began to align in his head. The old man’s words hit his engineering sense of optimization and love for pure efficiency with surgical precision. He understood his error. Until now, his close-combat style had relied on brutally breaking the enemy’s guard. It was destructive, yes, but incredibly unoptimal in terms of Vessel and splotch energy consumption.

He needed new software. A striking system that would allow him to instantly, clinically, silently, and completely effortlessly disable opponents from combat by targeting vital points and nerve splotches. Without making unnecessary noise, without wasting splotch energy on spectacular explosions, and most importantly—without destroying valuable material and loot that he had to sell to Silas later.

Dave threw the cracked clay cup onto the basalt plate, and the vessel shattered into tiny pieces with a loud, satisfying crash. He raised his right hand to eye level, slowly clenching his fingers into a narrow wedge and analyzing their biomechanics with a predatory, psychopathic smile that slowly bloomed on his face.

”Time to learn how to turn off enemies with one precise touch,” he muttered quietly under his breath, feeling a rush of adrenaline.

The rigor of defense was mastered to perfection. The time was coming to learn the harsh, clinical economy of elimination. The ”Quick” style was just being born in his head, ready to become his deadliest weapon in the dark depths of Crossgard.