"An Isekai Turned Sci-fi"

After the scorched corpse of the armored scorpion stopped twitching, Hajime crouched beside it without hesitation, already tearing into the husk with practiced precision. His gauntleted fingers shimmered with transmutation light, lines of alchemic energy crawling over the exoskeleton as he extracted the materials he needed. Chitin, subdermal plating, nodes rich with condensed mana—all of it fed into his ever-expanding arsenal.

Renji leaned against a boulder nearby, eyes scanning the barren cavern, Chrono Trigger holstered at his side. The subtle mana thrum it gave off still lingered in the air, like a faint ripple in time that hadn't quite settled. He checked the magazine instinctively—seven rounds left, plus one in the chamber. Just in case.

Yue, however, couldn't stop staring. Not just at the remnants of the battle—but at them. At the way Hajime seemed to command metal like an extension of his own will, and how Renji's gun had unleashed a force that bent the very air around it. For someone like her—sealed for centuries and raised in a world of magic incantations and ritualized power—this was something entirely different. Something wild.

Something brilliant.

She approached Hajime, slower this time, her golden eyes fixed on the parts he was carefully laying out beside him.

A one-and-a-half-meter-long barrel, copper rails gleaming with residual heat. Massive red-tipped bullets the size of short daggers. Reinforced steel components that snapped into place with magnetic clicks. It was both alien and beautiful.

And terrifying.

"What… what is all this?" Yue asked, her voice barely above a whisper. She stood close now—so close Hajime could feel her breath brushing his arm—but she wasn't just watching him anymore. She was studying everything.

"This?" Hajime grunted, tightening a bolt with a flick of transmutation. "It's a railgun. Think of it like… an anti-tank rifle that uses magnetism to fire projectiles at ridiculous speeds. Way more power than my last weapon."

Yue blinked slowly. "Tank?"

"Uh… something big. Heavily armored. Never mind that." He slid another component into place. "This rifle's a prototype. Schlagen. High risk, high reward. It's slow, heavy, and kicks hard enough to break bones. But if it fires? Whatever's on the other end is gone."

Yue leaned in slightly, staring at the crimson ammunition. "These bullets… are infused with mana?"

"Not exactly. The shells are designed to withstand the heat and velocity of magnetic acceleration. Mana helps stabilize the shot, but the punch comes from raw speed and kinetic force."

She fell silent for a moment, her expression hard to read. Then she looked over her shoulder at Renji. "And that thing you used… your weapon…"

Renji raised an eyebrow as she walked toward him. He tilted his head and tapped the grip of his sidearm. "Chrono Trigger."

She stopped a few paces away, eyes fixated on the sleek pistol at his side.

"I've never seen anything like it," she murmured. "Even among the oldest bloodlines, or the most ancient artifacts of my people… nothing bends time like that."

Renji drew the gun slowly, not to threaten—but to show her. The light caught on the polished slide, highlighting the intricate mana-reactive alloy woven into the steel. It looked like a modern relic, elegant and lethal.

"This design is based on something from our world," Renji said. "Colt 1911. Reliable. Elegant. But I wanted more than just stopping power. So I built a module inside the frame—one that lets me manipulate time on a micro-scale. Slow down perception, speed up reflexes. Sometimes I can even delay the impact of the bullet by a fraction of a second."

Yue's breath caught. "You're not just using magic… You're forcing the world to obey your design."

"Pretty much," Renji said with a smirk.

She reached out hesitantly, not quite touching the gun, but hovering her fingers just above its frame. "The magic I know… it flows with the world. It bends, dances. But this… this is. Precision. Innovation You don't pray for power—you build it."

Hajime glanced over, briefly pausing his work as he caught her expression—wide-eyed, fascinated, almost reverent.

He scratched his cheek, a little uncomfortable. She's seriously into this stuff… Never seen her like this.

"I thought you'd be scared of this kind of weaponry," he muttered.

"I am," Yue admitted. "But I'm more in awe. These aren't just tools. They're extensions of your will. You've turned destruction into an art."

Hajime blinked. She gets it…

Renji holstered Chrono Trigger again, his tone calmer now. "You've been sealed a long time. It's natural this stuff feels… overwhelming."

Yue shook her head. "No. Not overwhelming. Just… Mindblown. Like I've been staring at the world through a keyhole."

She turned back to Renji and knelt beside him again. This time, closer than before—her shoulder lightly brushing against his.

"Show me how you built this," she said, voice low.

"You want to learn?" Renji asked, genuinely surprised.

"I need to."

He exhaled through his nose, then offered her a faint smile.

"Alright then. Let's start with the basics."

The underground workshop pulsed with life.

Mana-powered engines throbbed like mechanical hearts, casting flickering shadows against the stone walls. Sparks danced across metal as arcane tools sizzled and whirred. Arrays of glowing blueprints hovered in the air, suspended by holographic magic fields—a fusion of alchemy, engineering, and pure human innovation.

Renji stood at the center of it all, sleeves rolled up, his hands moving with the finesse of an artist and the precision of a scientist. He was hunched over a metallic frame, tightening the final circuit-locks on Chrono Trigger. Beside him, Hajime Nagumo examined a smaller companion device, his fingers subtly weaving threads of transmutation magic through a crystal lattice embedded in its core.

Yue sat on a cold stone bench, her golden eyes wide—not with fear, but something bordering on reverence.

In her long life, she had seen kingdoms rise and fall, watched as sorcery tore apart mountains and reshaped the heavens. But this… this was unlike anything she'd ever encountered. These weapons weren't born of mana or willpower. They were designed—layered in logic, theory, and laws that existed beyond her world's understanding.

"What is this?" Yue finally asked, her voice low and awed. "These devices… they feel like magic, but they aren't. Not in the way I've known."

Renji smiled faintly, glancing at her without pausing his work. "That's because it's not just magic—it's physics, engineering, and a whole lot of trial and error."

"And a good chunk of transmutation," Hajime added, not looking up. "Don't forget who had to refine the base materials so they could handle the madman-level recoil systems."

Yue blinked. "Transmutation?"

Hajime chuckled. "Yeah. My class is Synergist. Back when I first arrived in Tortus, it sounded useless. A crafting job. But it's so much more than that. With it, I can manipulate matter at its most fundamental level—reshape metals, change their properties, create stable cores. Without it, none of this tech would survive a single shot."

Renji nodded in agreement. "What Hajime does is essential. He transmutes the alloys that can endure the magnetic stress from our railgun systems. You see this?" He held up a bullet glinting in the light, runes etched deep into its surface. "This isn't just a bullet. It's a mana-reactive core housed in a synthetic alloy Hajime created. It withstands temperatures that would melt normal steel."

Yue leaned forward, her voice filled with curiosity. "So… your synergy—it bridges the gap between magic and this… physics you keep speaking of?"

Hajime gave a small, proud smirk. "Exactly. I build the base, Renji pushes it past the limit."

Renji tapped the barrel of Schlagen beside him. "This baby works because we understand how forces interact. Magnetism, velocity, energy dissipation. The Lorentz Force—that's what accelerates the round. Imagine magic creating a field, and physics shaping how it behaves."

Yue raised an eyebrow, intrigued but confused. "Physics you keep saying that is that like an incantationin your world?"

Renji chuckled softly. "Yeah well, physics. It's basically the science of how everything works—how things move, how forces interact. And we engineers use that to design things that perform under specific rules. Magic is just one of those forces, but physics governs everything. It's what makes everything in this cave work."

He turned toward the workbench, where a half-finished schematic of the Schlagen lay. With a quick flick of his fingers, he summoned another hologram that hovered in front of him. It showed the layout of a magnetic coil system—concentric rings designed to accelerate projectiles to unimaginable speeds. Renji began to explain.

"The Schlagen uses an advanced form of what we call a railgun on my world. But instead of just using electricity, it uses a mix of magic and physics. The coils around the barrel create magnetic fields. And we use a force known as Lorentz Force to accelerate the projectile down the barrel."

Yue looked confused but intrigued. "Lorentz force?"

Renji smiled, clearly enjoying this challenge of teaching. "Right. So imagine a charged particle—say, an iron core inside the projectile. When that particle passes through the magnetic field, it gets pushed forward. The stronger the field, the faster it accelerates."

Yue's eyes widened slightly, her mind beginning to wrap around the concept. "So, the weapon doesn't rely on a mana blast or elemental power... but rather the physics of magnetic forces? You're using science to create a weapon of such power?"

"Exactly!" Renji's grin grew wider. "You've got it. The more we refine the field, the faster the projectile goes. You've seen the Schlagen's barrel, right? The longer the barrel, the more time the field has to act on the bullet, which makes it even faster."

He paused, then picked up one of the gleaming bullets. The projectile had an almost unnatural shine, etched with intricate rune-like designs.

"These bullets are another thing entirely. We use a special mana-conductive ore inside them, along with micro-runes to stabilize the magnetic field. But here's where the real fun begins—these things don't just hit a target. They penetrate."

Yue leaned in closer. "Penetrate?"

Renji nodded. "Most weapons rely on force at the point of impact. But these bullets—they travel so fast that they hit before most spells or shields even react. And once inside the target... they explode. The mana inside the bullet triggers a delayed explosion—after it's already breached whatever defense is in place."

Yue looked at him, fascinated. "You mean... this weapon doesn't just break through armor—it bypasses magic and destroys it from the inside?"

"Exactly," Renji said, his tone proud. "It's all about precision, timing, and force. Everything works in tandem. Magic alone couldn't do this. It takes physics—and a little creativity."

Yue nodded slowly, lips parted in wonder. "You've turned the invisible into something usable… something physical."

"It's the marriage of theory and magic," Renji said, wiping oil from his hands. "Back home, we spent centuries learning how the world works. Newton, Faraday, Einstein—they explained things most mages wouldn't dream of. But here, we apply that knowledge in a place where mana enhances every equation."

Her eyes widened as she took in the weight of his words. "You've combined magic and your world's technology in a way that makes conventional tactics useless."

Hajime leaned against the table, arms crossed. "And it's not just about raw force. It's about elegance. Transmutation gave me a way to make energy flow cleaner, bullets more efficient. Renji's designs make sure every motion counts. We're not just slinging spells—we're rewriting the rules."

Yue looked between the two of them, her voice a whisper. "And Tortus… it has no idea what you're building."

Renji smiled at her. "Not yet. But they will."

He beckoned her over to a display panel. A projection flared to life, showing a slowed-down simulation of Chrono Trigger's firing sequence. Magnetic fields curved and twisted in real time, energy surging along rail coils, propelling a projectile at hypersonic velocity.

Yue looked at the projection, unsure whether to marvel or recoil. It was beautiful in a strange, foreign way—symmetrical, clean, efficient. She had spent centuries learning the subtle balance of mana, the whispers of ley-lines and soulcraft. But here, everything was numbers, logic, and silence.

Yue stared, captivated. "And this… you created this from scratch?"

Renji shook his head. "No. We did."

Hajime grinned. "Transmutation formed the framework. Engineering refined the theory. Physics made it real. And a little bit of madness tied it all together."

Yue's heart swelled with something unexpected. These men weren't just outsiders—they were visionaries. Innovators.

She sat back slowly, absorbing the implications. In all her centuries, she'd never imagined such a weapon could exist—one that didn't channel magic, but outpaced it. She had lived through wars, watched cataclysms unfold—but this... this was something else.

Not magic.

Not miracle.

Just ruthless, scientific certainty.

Yue's voice softened, her gaze flickering between the two men. "I see now. You're not just making weapons... you're crafting a new reality, one where magic and science coexist, not as opposing forces, but as complementary tools."

Renji grinned, clearly pleased by her reaction. "Exactly. And the best part? We're just getting started."

Yue turned to look at him, a sense of wonder in her eyes. "I've lived for centuries and seen all sorts of magic, but this… this is something I've never even imagined."

Renji chuckled. "That's the beauty of it. Magic can only take you so far. With the right mix of science and magic, you can do things no one thought possible."

Renji leaned closer, his voice low. "We're not trying to impress anyone. These weapons weren't built for ceremony or spectacle. They were built to end fights before they start. And if anyone tries to take us down... they'll die before they even realize what hit them."

"And all of this," Hajime added, his tone grim, "was born from necessity. We've been betrayed, hunted, cornered. So we adapted. We stopped relying on the rules of this world—and started rewriting them."

Yue ran her fingers along the smooth metal, eyes wide and uncertain. What lay before her wasn't just power. It was a philosophy. An entirely new way of thinking. For the first time in centuries, she felt something stir deep inside—a spark of wonder that had long been buried beneath centuries of bloodshed and solitude.

And for the first time in a long, long life, she didn't know what came next.