My Perfect Isekai: Pragmatic Protagonist, Progression Fantasy and Strategy

The sulfurous heat of the fifty-third floor hit us like a physical wall the second we stepped through the stone portal. Behind us, the broken crest of Kaelar’s guard lay scattered in the dirt outside Oakhaven’s gates—a quiet, brutal reminder to the local syndicate that our progress was no longer open for negotiation. Before us stretched the Slag Rift, a terrifying chasm where rivers of white-hot liquid steel carved glowing channels through jagged basalt cliffs, plunging thousands of meters down into a bottomless, roaring abyss.

”O ja ciechrzrz!” Kaede’s high-pitched voice pinged in my left ear, her small spider legs tightening around the collar of my black coat as she adjusted her position on my pauldron. ”Szefie, ale tu piekarnik! Wilgotność spadła do zera, a temperatura powietrza na szlaku przekracza trzysta stopni! Dym wpada w filtry, ale moje czujniki optyczne widzą wszystko jak na dłoni!”

”Is the thermal isolation holding, Kaede?” I asked smoothly, keeping my hands tucked into the pockets of my long coat.

”Trzyma jak ta lala, szefie!” the spider chirped in her native Polish cipher. ”Twoja szafirowa tarcza chroni nas lepiej niż klimatyzacja w pięciogwiazdkowym hotelu! Ale na dole jest gorąco. Trzy duże sygnały na starym moście z kutej stali!”

Beside me, Shnee glided over the cracked basalt with feline grace. Her Celestial Silver rapier remained sheathed at her hip, but her sharp blue eyes scanned the swirling heat haze with absolute, cold focus. The ambient temperature inside our five-meter defensive sphere remained a crisp, refreshing eighteen degrees Celsius, completely unaffected by the roaring sea of liquid iron below.

”The air is thick with ionized metal, Dave,” Shnee observed, her voice calm and melodious. ”Normal spellcasters would find their mana weaves disrupted by the magnetic interference of the rift.”

”Normal spellcasters don’t run on a golden-sapphire reactor,” I replied with a faint, confident smile.

Deep within my chest, the newly awakened Pyrite Core hummed with a deep, resonant pulse. The breakthrough I had achieved in my bedroom had fundamentally transformed my energy system. The once-cloudy, restricted flow of my Jasper Core was gone, replaced by a pristine, gold-and-sapphire furnace that operated at a staggering three hundred percent efficiency. My modernized Vessel and widened energy pathways handled the massive energy throughput without a single tremor or spasm. Running our defensive sphere while moving through a three-hundred-degree hellscape required less than a fraction of a percent of my daily output.

As we reached the edge of the first iron span—a massive, rusted bridge hanging over the molten abyss—the ground trembled violently.

From the liquid steel below, three colossal shapes surged upward. They were Slag Sentinels—eight-meter-tall constructs of fused basalt armor, their joints glowing with white-hot iron and their eyes burning with crimson aggression. Each sentinel wielded a massive, ten-ton iron club, dripping with molten metal that splashed onto the bridge.

”Paczka trzech puszkarzy na szlaku, szefie!” Kaede reported, her tactical pings flashing in my vision. ”Waga każdego to lekką ręką piętnaście ton! Idą prosto na nas! Ich pancerze są utwardzone stopem płynnego żelaza!”

”Shnee, take the left,” I commanded calmly. ”Leave the center and right to me.”

”Understood, Dave,” she replied instantly.

The white-haired elf blurred into motion. She didn’t rely on complex incantations or brute force. Moving along the optimal line of force, she closed the distance in a fraction of a millisecond. Her Celestial Silver rapier struck like a flash of starlight, executing a surgical thrust directly into the Sentinel’s shoulder joint. She unleashed a concentrated wave of extreme, elemental frost straight into its internal circulatory pathways.

The sudden, violent thermal shock was catastrophic for the construct. The white-hot liquid iron inside its shoulder frozen in a microsecond, expanding rapidly and shattering the two-meter-thick basalt plating from the inside out. The Sentinel’s entire left arm detached with a deafening CRACK, crashing into the abyss below. Before the monster could rebalance, Shnee stepped inside its guard and delivered a second, precise thrust through its eye socket, freezing its core solid.

On my side, the two remaining Sentinels raised their ten-ton iron clubs simultaneously, bringing them down in a crushing, dual strike aimed at flattening us into the bridge.

I didn’t draw a weapon. I didn’t even take my left hand out of my coat pocket.

I simply raised my right arm with effortless, fluid precision, unbuckling a tiny mental valve within my energy conduits. Instantly, a layer of absolute, light-absorbing black Gōtai coated my entire right hand and forearm. The black energy shell hummed with an unyielding, absolute density fueled by the raw power of my Pyrite Core.

BOOM!

The two ten-ton iron clubs slammed directly into my outstretched, black-armored palm.

The impact generated a shockwave that blew away the surrounding sulfurous smoke and sent ripples across the molten steel below. But my feet remained planted on the rusted bridge. I didn’t give back a single millimeter. The kinetic energy of thirty tons of descending iron was absorbed, compressed, and neutralized instantly by my Gōtai shell.

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”Co za bezczelny blok!” Kaede squeaked in delight. ”Szefie, ty to po prostu zatrzymałeś dwoma palcami! A teraz dajesz czystą likwidację!”

”Liquidation engaged,” I murmured.

With a flick of my wrist, I channeled a double-voltage impulse of Sapphire Lightning straight through my palm and into the iron clubs. The golden-sapphire electricity didn’t just travel along the surface—it surged through the conductive metal like a tidal wave, flooding the internal cores of both Sentinels in a millisecond.

The internal electrical overload vaporized their mana nodes. Both eight-meter constructs froze mid-stride, their glowing crimson runes flickering violently before exploding into showers of harmless iron filings and cooling basalt dust.

I casually brushed a speck of ash from my sleeve as the purple core crystals tumbled from their shattered chests. I caught both crystals telekinetically and dropped them into my spatial pouch.

”Total energy expenditure: zero point zero two percent,” I noted calmly. ”The Pyrite Core is performing exactly as calculated.”

”Your control has reached an entirely new tier, Dave,” Shnee said, stepping back to my side, her rapier already pristine and free of ash. ”The fluidity of your energy distribution is flawless.”

”We’re just getting warmed up,” I replied. ”The boss of the Slag Rift is waiting on the fifty-fifth floor.”

We pushed deeper into the volcanic cavern, descending through the fifty-fourth floor with terrifying speed. Every patrol of lava salamanders, basalt gargoyles, and obsidian golems that tried to block our path was neutralized with clinical, mechanical efficiency. Shnee’s ice-coated thrusts and my point-blank kinetic bursts cleared each chamber in seconds, leaving behind a trail of shattered cores and valuable metallic scrap.

By the time we reached the archway leading to the fifty-fifth floor, the ambient temperature had spiked to over five hundred degrees. The chamber before us was a vast, circular arena surrounded by a roaring lake of liquid iron.

In the center of the arena stood the ruler of the Slag Rift: The Molten Warlord.

The monster was a twenty-five-meter titan of terrifying proportions. Its body was constructed from layered plates of dark, runic iron forged in the depths of the abyss. Its chest contained a roaring, furnace-like heart that pulsed with blinding golden-orange light, and in its right hand, it held a thirty-ton greataxe forged from solid, glowing slag.

”Szefie! Waga kloca to co najmniej pięćdziesiąt ton!” Kaede warned, her small voice echoing sharply in my ear. ”Pancerz z kutej runicznej stali ma grubość trzech metrów! Jego reaktor w klatce działa na dwustu procentach normy! Płynny metal na wokół niego ma temperaturę ponad tysiąca stopni!”

The Molten Warlord let out a deafening, metallic roar that shook the stalactites from the cavern ceiling. It raised its thirty-ton greataxe, causing the molten lake around it to erupt in massive geysers of liquid iron.

”Shall we combine our assault, Dave?” Shnee asked, her hand resting on her rapier.

”No need, Shnee,” I said quietly, stepping forward onto the narrow basalt path leading to the arena. ”I want to test the upper throughput limits of the Pyrite Core in a single, direct engagement.”

”Understood. I will secure the perimeter,” she replied, stepping back to guard Kaede and monitor the arena edges.

The Warlord spotted me approaching and took a massive step forward, its iron-shod foot creating a miniature earthquake. It raised the thirty-ton slag greataxe high above its head, bringing it down in a terrifying, diagonal cleave meant to bisect the entire basalt path and plunge me into the liquid steel.

The axe descended with blinding speed, its trajectory carving a line of white-hot plasma through the air.

I didn’t jump back. I didn’t draw a weapon.

I accelerated forward along a straight line of force, my boots barely skimming the burning basalt. As the massive blade came crashing down, I raised my right arm, unlocking a thirty-percent valve from my Pyrite Core.

Instantly, my entire arm was enveloped in a dense, shimmering shell of black Gōtai, intertwined with brilliant, gold-and-sapphire sparks.

BOOM!

The thirty-ton slag axe collided directly with my right palm.

The collision produced a sound like a naval cannon firing in an enclosed room. A massive shockwave blasted outward, blowing the liquid iron lake thirty meters into the air and shattering the basalt rocks on either side. But my feet remained firmly anchored. The titan’s colossal blow was stopped dead in its tracks by a single man standing on a narrow path.

The Warlord’s glowing crimson eyes widened in mechanical disbelief. It tried to pull the axe back, but my black-armored fingers were locked around the glowing blade like a vice of solid diamond.

”Is that the best thirty tons of slag can do?” I asked coldly.

I stepped onto the Warlord’s weapon, running up the length of the glowing shaft in a fraction of a second. Before the titan could react or raise its left arm, I launched myself into the air, reaching eye level with its massive, three-meter-thick chest plate.

I pulled my right fist back, condensing the full output of my Pyrite Core into a single, hyper-compressed point at my knuckles. The energy wasn’t just raw force—it was a harmonized, high-frequency impulse designed to shatter the atomic bonds of runic iron.

”Clinical Reset,” I declared softly.

THUMP.

My fist struck the center of the Warlord’s furnace heart.

For a millisecond, nothing happened. Then, a blinding flash of gold-and-sapphire light erupted from the point of contact. The high-frequency impulse flooded the titan’s furnace, instantly disrupting its thermal equilibrium. The liquid iron inside its core suddenly expanded beyond its structural containment limits.

BOOM!

A catastrophic internal explosion tore through the twenty-five-meter construct from the inside out.

The three-meter-thick runic armor plates burst apart, shattering into millions of glowing fragments. The Warlord’s massive form collapsed inward, dissolving into a harmless pile of cooling slag, iron filings, and steaming ash.

Floating in the center of the smoking debris was a massive, fist-sized purple-gold core crystal, pulsing with incredible energy density.

I caught the crystal casually in my right hand, feeling its warm, heavy weight before tossing it to Kaede, who caught it with a web-strand and stowed it safely in our spatial pouch.

”O kurwa, szefie!” Kaede yelled in sheer excitement. ”Jeden cios! Pięćdziesięciotonowy kloc zniknął jak sen jaki złotny! To był czysty przycisk ’delete’!”

”Energy expenditure: less than two percent,” I reported with a satisfied smile, flexing my right hand. ”The Pyrite Core provides a completely seamless integration of kinetic and elemental forces.”

Shnee walked up beside me, her eyes shining with quiet admiration. ”A magnificent display, Dave. The Slag Rift has been fully cleared.”

”And our budget for the Crossgard headquarters just gained another mountain of rare runic iron,” I added, looking toward the glowing portal that opened on the far side of the arena, leading to the fifty-sixth floor. ”Let’s gather the scrap and head back to Oakhaven for a well-deserved meal.”