My Perfect Isekai: Pragmatic Protagonist, Progression Fantasy and Strategy

Night descended upon the black basalt valley alongside a sharp, merciless drop in temperature. The damp mountain air swept down from the jagged peaks, carrying a wave of biting chill that crusted the edges of the roaring stream with frost. Yet near the small, stone-ringed campfire right outside the hewn wooden hut, a dry, comforting warmth prevailed. The red embers of dying oak branches cast dancing, elongated shadows across the vertical rock face, sharpening the rugged, titanic contours of the surroundings.

Dave sat on a flat, smoothed boulder with his legs crossed, his hands tucked deep into the pockets of his black leather coat. His body, which only a few days ago had been stiff, bruised, and strained from the grueling training sessions in the icy current, now rested in a state of absolute, laminar composure. His internal conduits operated on a pure idle state—zero unnecessary noise, zero turbulent energy bottlenecks, zero micro-vibrations in his tissues. The channels guiding his power remained completely empty and transparent, ready to engage a microscopic impulse in a fraction of a millisecond.

Beside him, on the opposite side of the campfire, Sensei puffed gently on his well-worn oak pipe. Blue smoke, scented with resin and pine needles, drifted straight into the thickening mountain fog. The old master studied the boy from beneath bushy, gray eyebrows, releasing slow, perfectly uniform rings of smoke from his lips.

”Quiet out here,” Sensei finally remarked, tapping the bowl of his pipe against the edge of a basalt stone. The impact sent a small shower of golden sparks cascading down. ”A week ago by this very fire, your conduits were buzzing like a leaky steam boiler. You crackled, glowed, and ground your teeth with every move. You shoved energy like a battering ram, wasting half your output on internal friction. Now... you rest like a black boulder at the bottom of a river. Not a sound out of you. Not a trace of you in the ether.”

”On a logical level, Sensei,” Dave replied without altering his posture by a single millimeter. His voice carried a dantean, unwavering calm. ”Unnecessary energy emission is a waste of fuel. If the conduits are strained, friction generates heat, efficiency loss, and needless pain. When friction drops to zero, movement becomes a pure mathematical formula. Absence of resistance means absence of energy loss. My body simply stopped fighting its own architecture.”

The old man smiled beneath his gray mustache, blowing out another cloud of fragrant smoke.

”A mathematical formula... A kid from Earth calculating the art of survival as a balance sheet of gains and losses. But I noticed something else during today’s trial with the forest lizard. You neutralized the creature in three seconds. Three precise strike points on its nerve clusters, zero spilled blood, zero ruined armor. You could have torn its head off with sapphire plasma. You could have snapped its neck with telekinesis. And yet you applied only as much pain as was absolutely necessary to bind its will. Not a grain more.”

Dave offered a light shrug of his shoulders, snapping a small oak twig in half and tossing it into the embers.

”Killing without a clear tactical reason is illogical and highly inefficient. Depriving a creature of life when it poses no direct threat wastes energy and generates chaotic friction. Furthermore, unnecessary slaughter ruins valuable resources—meat, hide, and ether crystals. I call it the economics of pain.”

”The economics of pain?” the old man repeated with amusement, raising an eyebrow.

”Precisely. Pain is nothing more than an information signal transmitted by the nervous system to the enemy’s command center. If the signal is clear, legible, and surgically precise, the target yields or freezes in paralysis without needing their biological structure destroyed. Why destroy the entire system when sending a brief ’stop’ command suffices? It saves time, fuel, and wear on one’s own conduits.”

Sensei narrowed his eyes, taking a long drag from his pipe while listening to the steady rush of the river.

”The economics of pain... A cold, calculating engineer’s mind. Many fools in this world would consider you soft because you don’t shed blood needlessly or fly into a rage like local brutes. But I saw your eyes when you mentioned your girls back at the manor. I saw what happens to your sapphire light when the safety of your domain is on the line.”

Dave slowly opened his right, sapphire eye. In his gaze, there was no longer a trace of mathematical detachment or casual ease—instead, a hard, deep, and dangerous glare flared up, resembling molten titanium inside a reactor.

”Because there is a clear, unyielding boundary, Sensei,” he said quietly, his voice sounding like a heavy ram striking a basalt gate. ”I call it the Red Line.”

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”The Red Line?” the old man repeated, straightening his back slightly and setting his pipe on the stone.

”Precisely. As long as someone operates outside that line—whether they conduct business with me, compete on market terms, attempt to cheat me out of gold, or simply step into my path out of their own arrogant stupidity—I apply the economics of force. I can ignore them, incapacitate them, mock them, force a bow, or strip them of their wealth. It’s a clean tactical and business game. But if someone deliberately and with premeditation crosses the Red Line... if they raise a hand against my family, plot an attack against Shnee, Elena, Luthia, Mina, Ria, Karys, or Kaede, or attempt to breach our sanctuary... then the rules of economics cease to exist.”

The old man remained silent for a long moment. Around the campfire, the only sounds were the quiet crackle of snapping twigs, the whisper of the wind, and the steady, bass rumble of the stream.

”No negotiations then?” Sensei asked, looking straight into the boy’s dangerously calm eyes.

”Then comes pure, ruthless, and immediate erasure,” Dave answered without the slightest hesitation. ”No speeches, no drama, no lingering debts, no mercy, and no second chances. Anyone who breaches the Red Line ceases to exist in my system. They are wiped from the spreadsheet like an invalid data record. My family is the one thing in this world that carries no market valuation. There is no profit margin on that point.”

Sensei blew out the last of his smoke and, for the first time since the training began, nodded with a gravity that blended respect with deep, quiet admiration.

”Good,” the old man grunted, tightening his grip on his oak staff. ”A true Apex Predator must know where the hunting grounds end and the nest begins. Without a Red Line, you become either a mindless slaughterer or a naive victim waiting to be torn apart by hyenas from the Guild or Halgard. You are neither. You are a monolith.”

The old man rose slowly from the boulder, leaning on his bamboo staff. He poked the tip of the staff into the glowing embers, sending a black cloud of golden sparks into the night sky.

”Your foundation for the Style of the Sapphire Flow is complete, kid,” he said, gazing toward the dark wall of the forest. ”Your body has mastered zero-resistance movement. Your conduits have grasped laminar ignition. Your mind has set an impenetrable boundary. It’s time to end the dry drills in this safe valley.”

Dave looked up, straightening his posture.

”Moving on to real practice?”

”Yes,” Sensei replied with a predatory, rugged grin. ”Tomorrow we head deeper into the Unknown Lands beyond the city. You’ll see how your Red Line, Lynx Footwork, and Inertia Lock hold up against a genuine, unpredictable threat. Gather your strength, Dave. Your year of grueling labor is drawing to a close, and your girls in Crossgard won’t wait forever.”

For a long time, neither of them spoke. The wind from the ridge gathered strength, whistling softly through the crevices of the black basalt and scattering embers from the campfire across the valley floor. Dave stared into the darkness, mentally analyzing every component of his newly forged combat infrastructure.

He remembered how, before embarking on this wilderness trial, he had bound Kaede to Shnee via a sapphire pact-thread. The little spider familiarch on his shoulder now served the girls at the manor as a stationary radar and live data relay. Everything Kaede detected within a five-hundred-meter radius around the basalt stronghold was instantly transmitted to Shnee’s consciousness in their private Polish cipher—unbreakable by local guilds. Luthia and Elena maintained a firm grip on the finances, dismantling the profit margins of Upper City merchants and securing steady supplies of high-calorie meat for Mina.

”I remember,” Sensei spoke up suddenly, breaking the silence. ”When you first stood in that river basin, you thought only of physical brute force. You tried to flex your muscles to dominate the inherent magic of this world. But magic here... it isn’t about arm strength, kid. Magic is entirely about resistance and flow.”

”On a logical level,” Dave interjected, tapping his heel lightly against the black rock. ”Force without control is merely loud noise. If you strike with full power but your body resists its own energy, half that force rebounds into you as a destructive feedback wave. That’s precisely why I developed the Lynx Footwork and Inertia Lock. Instead of fighting the momentum of an enemy strike, I let it pass through my body with zero resistance, then return it with triple the output directed at the weakest node of their biomechanics.”

Dave swept his eyes across the shadows encircling the clearing. Every detail of the surroundings—from the alignment of pine needles on the branches to the microscopic vibrations of the ice crust over the stream—arranged itself in his mind into a coherent grid of data. Training under Sensei had not forced him to abandon his analytical nature; on the contrary, it taught him how to leverage every available resource in the most cost-effective manner.

”In the long run,” Dave continued, tossing another small twig into the fire, ”the hardest part isn’t defeating an enemy, but ensuring that a single victory requires no constant revisions. That is precisely why Karys’s armor must be crafted from seamless basilisk hide without guild markups, and why the debtor ledgers in the Lower City must be acquired by Silas without fanfare. When every component of the machine runs without friction, victory becomes a mere byproduct of sound engineering.”

”And that is the true core of the Sapphire Flow,” the old man grunted with satisfaction, tapping the pipe against his palm. ”Not resistance. Not arrogance. Just pure, soundless flow.”

Dave stood up from the rock, drew himself up to his full height, and looked south, where the distant glow of the massive metropolis shimmered beyond the ridge of black spires. He smiled faintly to himself, slipping his hands deep into the pockets of his black coat.

”On a logical level, Sensei... it’s about time to see how this world reacts to the finished product.”