MRUCM 01

Chapter 01

“So you really have no intention of getting married?”

His only older brother asked.

Baek Kang-jin leaned back against the bench and replied.

“No.”

“Why do you have to be so blunt about it? You’ve already established yourself well enough.”

“Brother. I have my own plate full. In a world where just taking care of my own life is a struggle, who am I supposed to take responsibility for?”

This was genuine.

The title of microbiologist.

It might sound impressive on the surface, but in reality, it was an endless game of hide-and-seek with viruses.

The world beyond the microscope was far from romantic.

Watching microorganisms desperately struggling to survive made human relationships feel like an extension of that parasitism and symbiosis.

In other words, it was exhausting.

“Still… I think it’s wonderful.”

His older brother Baek Kang-woo smiled shyly.

He’d been like this ever since he started dating his sister-in-law.

A face that looked like he alone had taken all the happiness in the world.

Honestly, sometimes Baek Kang-jin was envious.

“Let’s go in.”

Following his brother’s lead, he stood before the glass window of the nursery.

Beyond the transparent glass, red lumps wrapped in swaddling clothes were squirming around.

Among them was supposedly Baek Kang-jin’s niece.

“There she is, our daughter.”

His brother pointed.

A newborn was visible.

“……”

Ugly.

That was his honest impression.

Just how many years would it take for that thing to function as a proper human being?

Truly the worst cost-performance ratio.

But then.

A nurse came out holding the baby.

Unable to resist his brother’s urging, Baek Kang-jin awkwardly received that tiny life form in his arms.

Light.

And warm.

The moment the squishy flesh touched his arm, fear rushed over him.

It felt like he might crush it if he handled it wrong.

That was when it happened.

A tiny, fern-like hand flailed through the air and tightly gripped Baek Kang-jin’s index finger.

“……!”

His heart dropped.

A grip so weak it could hardly be called strength.

But at that moment.

Neurons in his brain simultaneously released chemicals.

As a biologist, Baek Kang-jin could recognize it.

‘Ah…’

It was over.

Baek Kang-jin realized.

For this tiny little bundle of blood, he could throw every shred of efficiency and logic from his life into the trash.

It was the moment a weakness was born in the life of Baek Kang-jin, the unfeeling, tearless rationalist.

Gates.

Dimensional rifts.

Words that he’d only ever seen in disaster movies began dominating the news headlines.

Kang-jin was on the subway coming home from work.

Kwa-rur-rung.

A roar sounded.

Followed by screams.

Baek Kang-jin was powerless.

And then—blackout.

When he opened his eyes.

The world he had known was no longer Earth.

Ten years.

During a time enough for mountains and rivers to change, Baek Kang-jin worked like a madman.

This place was similar to the worlds in fantasy novels.

There was magic, there were monsters, and irrational violence ran rampant.

But modern knowledge was still valid here.

Luckily, he caught the eye of a great mage and became his disciple.

His master was a cranky old man, but his knowledge of magic was genuine.

Baek Kang-jin absorbed everything like a sponge.

From basic magic to ancient language interpretation, to the structure of mana circuits.

He cut back on sleep, skimped on meal times, and devoted himself to research.

He had to survive.

He had to return to Earth.

And on the day he finally descended from the tower.

His master clicked his tongue and said.

“Ruthless bastard. You’re the only one who’s drained my resources this quickly.”

“I’ll take that as a compliment.”

Kang-jin didn’t look back as he came down from the tower.

And he wandered the world.

To understand this world’s ecosystems, culture, and the limits of its magic.

And now.

Baek Kang-jin sat in a secluded tavern at the edge of the dwarves’ village.

Thud.

Thud.

Thud.

The ground shook.

Dust from the ceiling fell onto his beer mug.

“Here he comes again.”

Across from him, the dwarf elder Garin spoke with a bitter expression.

“This month he’s too early. We haven’t even reached half our mining target yet.”

Outside grew chaotic.

Screams.

Buildings collapsing.

And above all that noise, the sound of enormous wings flapping.

It was a dragon.

The lord of this mountain range, and a vicious loan shark.

The Red Dragon, Balakas.

Every month he’d come here and sweep away all the gold and gems the dwarves had sweated to mine.

“I suppose I should go out. If I don’t, he’ll set everything on fire again.”

Garin said weakly.

His hunched back looked defeated.

This elder, usually so boisterous and bold, would lose all his spirit whenever that lizard bastard showed up.

Baek Kang-jin looked outside through the crack in the window.

An enormous reptile covered in red scales was landing in the village square.

Smoke from its nostrils carried the acrid smell of sulfur.

“Wretched ground-crawlers. Is my tribute prepared?”

Arrogant.

His voice dripped with a sense of superiority.

The dwarves pulled out carts loaded with gold bars.

The dragon saw this and snorted mockingly.

“Too little. Far too little. Are you testing my patience?”

“Th-that’s not it! The veins haven’t been productive this month, so…”

“Excuses are a sin. The price shall be your lives.”

Crunch!

The dragon’s forepaw crushed a dwarf.

He couldn’t even scream.

He just burst.

Red blood stained the plaza floor.

“……”

Something boiled up from within.

Baek Kang-jin wasn’t a champion of justice.

Nor was he the kind of fool who risked his life for others’ affairs.

But this crossed the line.

That disgusting attitude of taking pleasure in bullying the weak.

That sight of someone drunk on their own power treating lives like toys—it didn’t sit well with him.

Especially because it was exactly the type Baek Kang-jin hated the most.

‘Just like a pest.’

An impulse surged.

But reality was harsh.

Baek Kang-jin was only a 5th-circle mage.

Before a dragon, he was nothing but kindling.

Could he even pierce a single scale with magic?

Impossible.

Like throwing an egg at a rock.

A frontal assault had no answer.

But.

Baek Kang-jin had a weapon they didn’t know about.

‘Microorganisms.’

He pulled a small glass bottle from his pocket.

A transparent liquid sloshed inside.

The mages here were obsessed only with turning mana into fireballs or ice spears.

That was an inefficient approach.

Mana is energy.

And energy can manipulate matter.

Which meant—

It could also manipulate matter in the invisible microscopic world.

For the past few months.

He’d been hiding out in the dwarf village, repeating experiments.

A fusion of magic and biology.

Virus modification—his specialty field.

‘Dragons have high magic resistance.’

Their skin is tough, and they repel most curses.

But what about their immune system?

Dragons are born as apex predators.

They’ve probably never been sick.

In other words, their immune system is like a hothouse flower.

“Let me show you the power of science. You overgrown lizard.”

What he held wasn’t ordinary poison.

It was a dragon-tailored biological weapon, its genetic code redesigned through magic.

Named the Raging Dragon Plague.

A subspecies of the rabies virus with a 100% fatality rate.

The plan was simple.

Dragons love gold.

They have a habit of flaring their nostrils and inhaling deeply when they catch the scent of gold.

Baek Kang-jin approached near the plaza.

And checked the direction of the wind.

No wind.

But that didn’t matter.

He could simply use a bit of magic to carry the breeze.

“……”

The dwarves were retreating in fear.

Balakas was toying with the dwarf corpse, nudging it with his claws.

“Double next month. Understood?”

Just as the dragon lowered its head to smell the gold bars in the cart—

Baek Kang-jin snapped his fingers.

‘Wind Breeze.’

A very subtle wind.

The vaporized liquid rode the breeze and was drawn into the creature’s nostrils.

“Sniff… sniff…”

The dragon twitched its nose.

There would be no smell, no taste.

The Raging Dragon Plague virus rode the wind and entered the dragon’s body.

“Look forward to next month.”

With a great flap of wings, Balakas vanished into the sky.

The dwarves sighed in relief.

But soon their expressions darkened.

Next month would come, and someone else would die.

Elder Garin beat the ground and wailed.

“Balakas! I curse you with all my soul!”

Baek Kang-jin tapped Garin’s shoulder.

“Elder. You won’t need to prepare for next month.”

“What do you mean?”

“He won’t be coming back.”

Garin looked confused.

Baek Kang-jin shrugged and returned to the tavern.

A week passed.

In the forest near the dragon’s lair.

Baek Kang-jin was observing the dragon’s den with magic.

The virus’s infiltration route: nasal mucosa, then olfactory nerves, finally the brain.

The magically enhanced virus easily breached the blood-brain barrier.

It was about time.

For symptoms to appear.

No matter how strong the dragon’s immune system was, it didn’t matter.

Because the Raging Dragon Plague’s specialty was disrupting immune cell communication.

Moreover, the virus’s outer coat was coated with proteins identical to normal cells.

It would have penetrated brain cells without any interference.

“I’ve given it enough time.”

Baek Kang-jin lightly snapped his fingers.

Click!

The kill switch activated.

The magical signal reached the virus instantly.

KUUOOOOHHHHH!!!

A scream that shook the entire mountain range.

A pained shriek, like scraping metal, echoed through the air.

“It’s going to hurt quite a bit.”

Baek Kang-jin curled the corner of his mouth.

In modern medical terms: acute encephalitis.

The virus proliferates explosively simultaneously throughout brain tissue.

Then the brain swells up.

What happens when the brain expands inside a rigid skull?

He’d be feeling the agony of his own head being crushed from the inside.

Thud! Crash!

The massive dragon burst out of the cave.

His condition was horrific.

His eyes were so bloodshot they’d burst, tears of blood streaming down, and white foam filled his mouth.

“GRAAAAHH! MY HEAD!”

Balakas smashed his head against the rocky mountain like a madman.

CRASH!

Boulders shattered and a rockslide occurred.

But the pain didn’t stop.

‘Reason stripped away by madness.’

As his frontal lobe melted away, the boundary between reality and hallucination would have collapsed.

Everything in sight would look like monsters trying to kill him.

Even the smallest light or rustle of leaves would feel like an awl piercing his brain.

“GET AWAY! ALL OF YOU, GET AWAY! AAAAAHHHH!”

Balakas wildly sprayed his breath at empty air.

At the same time, startled by his own shadow, he screamed and stumbled backward.

The mighty dragon, terrified, was pissing himself.

‘Utterly pathetic.’

Now for the final stage.

Balakas was now feeling a burning thirst.

The high fever from the encephalitis had dried up all his bodily fluids.

Staggering, Balakas crawled toward a nearby lake.

“Water… water…”

He plunged his snout into the lake.

“Kek! Keheh! Krrrk!”

The moment he tried to swallow water.

His throat muscles spasmed uncontrollably, tightly blocking his airway.

Hydrophobia.

A symptom where he’s thirsty, but the mere sight of water triggers convulsions.

With his airway blocked, the dragon choked and rolled on the ground.

Even the muscles that moved his lungs began to paralyze.

“……”

Baek Kang-jin slowly walked out of the forest.

His eyes met Balakas’s.

The creature’s pupils were already dilated.

But instinctively, Balakas seemed to realize who the culprit was.

“Yo… you… did this?”

“So what?”

Baek Kang-jin replied dryly.

“How dare… a mere human…!”

With his last strength, the dragon raised his forepaw toward him.

But that was as far as it went.

Thud.

The paw fell limply to the ground.

His nervous system was completely severed.

The massive body stiffened, then collapsed sideways.

The ground shook as if an earthquake had struck.

Pshhhh…

His final breath escaped through his nostrils.

For the end of a “great race,” it was utterly pathetic.

‘This is the beauty of biology.’

Dragon Slayer.

A grandiose title, but he felt no thrill.

The dwarves worshipped Baek Kang-jin like a god.

But he was more interested in the loot than the cheers.

The dragon’s lair.

Specifically, the dragon’s treasure hoard.

He roughly swept gold coins and jewels into his subspace.

What caught Baek Kang-jin’s interest was the library.

Magic tomes collected over thousands of years by the dragon.

Secret manuals written in ancient languages, elemental script, and runes—these were the core.

With these, his research could advance several steps further.

And the most important thing.

The dragon’s heart.

A crystallization of immense magical power.

“……”

Baek Kang-jin held the dragon’s heart in his hand.

Its searing heat radiated through his palm.

If he absorbed this power, he would no longer remain within human bounds.

Baek Kang-jin hid in a sanctuary that no one had found.

He could go out into the world later.

He needed to hole up here and make the knowledge and power his own.

Whether it took ten years or twenty, it didn’t matter.

What mattered was.

Becoming an absolute being that no one could challenge.