"Ouch…"
The word escaped Kai's mouth before he fully woke. His back throbbed as he pushed himself up from the cold, unforgiving floor. For a second, he just lay there, stunned, his breath shallow and uneven. Then the ache pulled him fully into consciousness.
*I fell off the bed…?*
He blinked, clearing the fog from his mind — only for confusion to slam into him harder than the floor had. He froze, eyes widening as he actually *looked* at the place he had landed in.
This was not his apartment.
Not even close.
The room around him was a strange blend of old-world craftsmanship and industrial brutality. Floor-to-ceiling oak cabinets lined the walls, their once-polished surfaces scarred by scorch marks and chemical stains. Heavy mahogany paneling bore deep scratches as if someone had lost their temper — or conducted experiments with explosives.
A thick steel plate reinforced the center of the floor, each shift of his weight sending a faint metallic echo through the room. The air smelled faintly of oil, dust, and something sharper — ozone, maybe. Something that hinted at danger.
Kai's gaze shifted to the massive circular bay window dominating the far wall. Its glass was leaded and tinted, sealed shut with brass-bound rubber gaskets. Outside, only a hazy smear of gray could be seen through the thick smog. Near the sill, a delicate clockwork mechanism clicked to life, a tiny mechanical arm wiping condensation from the center pane with dutiful precision.
The sound was almost comforting.
Almost.
But the room's centerpiece stole that illusion away. A colossal cast-iron workbench occupied the space like a beast crouching in wait. Its surface overflowed with half-finished projects — disassembled chronometers, coiled copper wiring, tiny vials of luminescent fluid that looked suspiciously unstable. A desk lamp powered by a miniature boiler hissed sharply as it cast a bright, white beam across the chaos.
This wasn't a bedroom.
It was a workshop.
"What the hell…" Kai whispered, pushing himself to his feet.
He staggered toward a tall mirror framed in smoked amber glass. The tint softened the reflection, lending it a warm, nostalgic glow that didn't match the cold dread crawling up his spine.
Kai braced himself and leaned in.
The boy staring back at him was a stranger.
Long, slender hands — but strong, calloused, and slightly flattened at the fingertips, as if accustomed to delicate mechanical work. Skin pale but not unhealthy. A sharply defined jawline, a narrow, elegant nose. Thick hair, dark brown drifting toward black, unruly and too long, falling across eyes that were not his.
A face somewhere between handsome and ethereal.
A boy who looked… sixteen? Seventeen?
Kai took a slow breath.
His reflection breathed with him.
"I've been turned into a teen boy," he muttered, louder than he intended, voice cracking with shock.
But shock didn't last long. Not for him.
He had been a mechanical engineer in his past life — one who favored logic over panic, calculation over emotion. His mind was already moving, gears spinning, processing.
I got transmigrated into the body of this young boy.
But what that voice meant by dual existence.
The idea was absurd. And yet… so was the room.
Before he could think deeper, a loud thud slammed against the door.
"Elias! Are you awake? Get ready quickly or you'll be late for school!"
Kai went rigid.
*Elias?*
His new name.
He didn't have time to react. The door swung open without waiting for permission.
A man stepped inside — tall, lean, and carrying the presence of someone who took life too seriously. He looked around twenty-six, with a sharp, angular face and clear eyes that reflected both intellect and perpetual irritation. His nose was straight and proportional, and his thin lips pressed into a line that suggested he didn't smile often.
Kai stared.
The man stared back, unimpressed.
"Elias, what are you doing? Standing there like an idiot and staring at yourself?" he snapped. "Move. You're going to be late."
Stress twisted in Kai's gut. Instinctively, feeling cornered, he blurted out the first word that came to him:
"Yes, Dad—"
The man froze.
Then his expression darkened like a gathering storm.
"*Dad?*" His jaw clenched. "Do I look that old to you? Idiot, I'm your big brother. I'm only twenty-six."
Kai winced internally.
*Great start. Truly spectacular.*
But even as panic fluttered in his chest, another part of him — the cautious, cold, analytical part — was already adjusting, adapting. The world had changed; he needed to change with it.
He straightened, lowered his gaze, and forced an apologetic tone. "Sorry, brother. Just joking."
"Is this the time for jokes?" the man snapped. "Go shower and get ready. Breakfast in ten minutes. Move, you brat."
With that, he left the room, muttering under his breath.
The door shut.
Kai let out a slow exhale.
Silence settled like dust.
Then he whispered, "This is insane…"
But insanity didn't excuse stupidity. And letting panic take over would be the fastest way to die in an unfamiliar world. If he really was in someone else's body, then the original owner's identity would be his only shield for now.
He needed information.
Kai began searching the room — efficiently, methodically. The same way he would disassemble a malfunctioning engine, checking each part, each piece, each detail. The workshop was cluttered but organized. Tools arranged with obsessive precision. Schematics pinned to corkboards. Notes scribbled in tight handwriting he now instinctively recognized as his own… or Elias's.
Several textbooks caught his attention, stacked neatly on a shelf.
*Advanced Hydraulics II.*
*Aether Conduction Principles.*
*Applied Mechanical Resonance.*
*Academy of Applied Hydraulics and Aether Theory — Year 3.*
Kai stared at the titles.
"Hydraulics… and aether?" he muttered.
Magic and machinery.
Science and sorcery.
A hybrid world.
Something in his chest tightened — not fear, but an old familiar spark. Curiosity. The same instinct that once pushed him to dismantle machines just to understand how they worked.
But beneath that spark lurked something darker. More cautious. More like Sunless — quiet calculation, quiet dread, quiet resolve.
He couldn't trust anything here.
Not his new body.
Not this "brother."
Not the world outside the smog-sealed window.
And especially not the identity he had inherited.
Kai straightened slowly, closing his fingers into a fist.
"Fine," he murmured to himself. "New world… new body… new name."
He looked back at the amber-tinted reflection.
"At the very least," he whispered, voice steady and cool, "I'm not going to die once again just because fate threw me somewhere strange."
He turned away from the mirror and toward the door.
If he wanted to survive, he first needed to understand the role he was expected to play.
Elias.
A student at the Academy of Applied Hydraulics and Aether Theory.
A boy with a brother who watched him too closely.
A life he now had to live.
Kai's expression hardened — calm, unreadable, quietly dangerous.
"Let's see what kind of world I've fallen into," he said.
And with that, he stepped forward, ready to face a reality that wasn't his.