Crackle. Fwoosh. Fwoosh.
As Sabi River stepped into the cave, torches inside the pitch-dark cavern spontaneously ignited.
Looking back, the entrance still showed the view of the canyon outside.
From the outside, it looked like nothing more than a rocky cliff, but stepping in revealed a hidden cave.
The result of a barrier.
Step, step.
Sabi River walked forward without hesitation.
He had encountered countless barriers like this in the Demon Realm.
And if one were to rank them, this would fall under a low-grade barrier.
The cave was deeper than expected.
It was after walking for quite some time—
Swoosh!
A spear suddenly shot out from the darkness ahead.
But Sabi River didn't even blink.
Shlick!
The sharp spear pierced through his abdomen and flew past.
An illusion.
The spear that passed through his belly vanished like smoke.
Barriers used in the Demon Realm were nearly identical to the mechanical formations of the Central Plains.
However, while mechanical formations required substantial physical construction, barriers could be maintained purely by mana.
Whoosh! Whoosh!
Fwoooosh!
This time, flames suddenly erupted and two spears came flying at him simultaneously.
Again, Sabi River didn't flinch.
Illusions.
The flames weren't hot, and the spears pierced right through his body and vanished.
If one even slightly felt threatened by these illusions, real damage could be inflicted in that moment.
Sabi River, who had been walking forward, suddenly came to a halt.
The air had changed.
From here on, the attacks wouldn't be illusions anymore.
He closed his eyes and felt the mana gathered around his heart.
Since his middle dantian hadn't yet formed, his mana and inner energy remained separate.
Because of that, even though he had poured all his strength into his light footwork, the demonic energy absorbed from the Demon King remained completely intact in his heart.
Finally, Sabi River opened his eyes.
He quietly muttered,
"Shield."
In that instant, a faint aura spread over his entire body, forming a thin barrier.
He stepped forward again.
In a flash—
Crackle! Zap!
Two orbs came flying at him, emitting electric pulses.
These weren't illusions.
They were real.
Lightning Bolts.
Sabi River swiftly stepped aside, dodging the lightning bolts.
But soon after, fireballs began to rain down.
Fwoosh! Crackle! Fwoosh!
These, too, were real.
If he stood still thinking they were illusions, he'd burn to death.
He twisted his body as much as possible to avoid them, but two fireballs struck him directly.
Boom! Fwoosh! Fwoosh!
The fireballs scorched the thin barrier and then dissipated.
'Tch, annoying.'
Still, he had now overcome most of the traps.
'Only one left now?'
Sabi River pulled out a dagger from his waist.
Step, step.
At some point, a sweet melody began to play, and a sugary scent wafted to his nose.
And then came an overwhelming drowsiness.
Just before his eyes closed, Sabi River stabbed his own thigh with the dagger.
"Ghk!"
His mind snapped back into focus.
In an instant, the melody and scent vanished as well.
A dead end.
"Heh heh heh. You've finally arrived."
Blood dripped from his thigh.
It might not seem too difficult at a glance, but for someone from the Central Plains, finding this place at all would be nearly impossible.
You needed to be able to sense mana.
And to pass through the barrier, your internal mana had to resonate with the barrier's nature.
Even if someone from the Central Plains were lucky enough to enter, if they didn't know the attributes of mana, there was over an 80% chance they'd die inside.
Sabi River gazed at the wall at the end of the path, took a deep breath, and walked straight into it.
As he passed through the wall, a massive hollow chamber appeared.
The chamber was lit all around by torches.
"Mana Point."
Sabi River muttered softly.
A term used in the Demon Realm.
At the center of the chamber was a chest.
When he opened it, inside was a gem glowing with a brilliant blue light.
Inside the gem, light swirled as if it were alive.
A magic core.
And a top-grade one at that.
"Heh heh heh. I finally got it. A top-grade magic core!"
A smirk tugged at Sabi River's lips.
Beside the core was a small vial containing a red liquid.
Healing potions.
Five in total.
"Not bad at all."
Grinning, Sabi River picked up the magic core.
Crackle. Zap.
The light swirling inside the gem occasionally pulsed, as if the gem were alive.
Of course, it wasn't alive.
That's precisely why it was here now.
"Heh heh heh. Time to dig in!"
Suddenly, veins bulged on the back of Sabi River's hand.
Crackle!
A powerful energy wave surged from the magic core.
Moments later, pure white energy and blue energy began swirling and were sucked into Sabi River's palm.
***
The Demon King's army suddenly appeared in the Central Plains one day.
And a bloodbath unfolded without warning.
In just six months.
In six months, the entire population of the Central Plains was wiped out.
Most were either killed or abducted.
But the Demon Realm hadn't done this overnight.
They had planned and prepared for a long time.
However, there was a slight issue with dimensional travel.
There was a time lag between the transportation of living and non-living things.
Even if both were sent at the same time, non-living items arrived far faster.
On average, a 20-year difference.
In other words, even if they attempted dimensional transfer simultaneously, non-living items would arrive in the Central Plains twenty years earlier.
And in a world like the Central Plains, where mana didn't naturally exist in the air...
Items like mana potions, magic cores, and dragon hearts were absolutely essential.
So the Demon Realm scattered all the necessary supplies across the Central Plains in advance. And they protected them with barriers.
Which means—magic items had already been hidden throughout the Central Plains at least a decade earlier.
In fact, if you included the time they spent on experiments, some Demon Realm items had existed here long before that.
The Orthodox Alliance eventually realized the truth and began finding some of the barriers, but most of their members died to traps.
They simply weren't familiar with mana-powered barriers.
"But my situation is different."
Sabi River opened his eyes and muttered quietly.
A faint red glow flickered in his pupils before fading away.
"Phew..."
He let out a long breath.
A hot energy rose in waves from his entire body.
Two full days had passed.
The mana accumulated in his heart surged and burst through his meridians.
Circulating smoothly through his bloodstream, the mana flowed down to his lower dantian and converted into internal energy.
His middle dantian had opened as well.
Normally, opening the middle dantian through internal energy training was extremely difficult, but with mana, the process was significantly easier.
That's because mana originally gathered in the heart.
However, the vessel that holds mana isn't the middle dantian—it's the heart itself.
Sabi River had opened his middle dantian in order to cultivate both mana and internal energy equally.
The demonic power he had absorbed from the Demon King during his regression had turned out to be surprisingly useful.
"No matter how many times I experience it... absorbing a magic core always feels amazing. Hehe."
Nagong Heart Technique .
A secret technique he had created, mastered, and named himself in the Demon Realm.
A heart technique that absorbs mana from external sources.
Unlike the mystical pills gained through fortuitous encounters in the Central Plains, this one had virtually no side effects—a major advantage.
With a top-grade magic core like this, using the Nagong Heart Technique for two days allowed him to absorb its mana effortlessly.
Sabi River tucked the five healing potions from the chest into his robe and rose to his feet.
He raised his right hand and focused his consciousness. A blue orb formed in his palm.
Crackle! Crackle!
Waves of energy pulsed violently.
It was far larger and more powerful than the tiny orbs he had created back at the academy.
In the next moment, Sabi River thrust out his hand.
The blue orb in his palm shot out and slammed into the wall of the chamber.
Boom! BOOMBOOMBOOM!
A thunderous explosion rocked the chamber, shaking the earth itself.
A large hole had been blasted into one side of the wall.
From the far end, a faint light seeped in.
It was the exit.
"Now I'll retrieve them all... one by one. Hahaha!"
Sabi River laughed heartily and strode forward.
***
"Hmm. He's late."
Dean Juyucheon stroked his beard, frowning slightly.
He sat on a temporary platform set up in front of Yongho Hall's courtyard.
With his eyes gently closed, Juyucheon sat surrounded by instructors responsible for first-year students.
Across from them was a temporary sparring stage, around which a large crowd had gathered—mostly students of the academy.
"Didn't they say the duel was scheduled for today?"
"Apparently, it's a match to decide the assistant spear instructor for the first-years."
"Who cares about a spear instructor? No one learns boring spear techniques these days. Wait, is it that guy Sabi River?"
"Yeah. Honestly, I don't care who wins, but it's rare to see instructors duel like this."
"Then why isn't it starting yet?"
The courtyard buzzed with chatter from the students.
Among them were Yeon Wookyung and Gok Bohok's group.
Gok Bohok smirked.
"Maybe the guy figured out who he's up against and ran off?"
"That'd make this a lot less fun."
Yeon Wookyung narrowed his eyes and turned his head.
His gaze landed on Maeng Sondeok, the participant in today's duel.
Maeng Sondeok was twisting his body and holding a spear in both hands.
At that moment, he stepped onto the duel stage and saluted the platform.
"Respected Dean and instructors, when will the match begin?"
"Hmm. Just a little more patience, please."
Only then did Dean Juyucheon open his eyes and respond.
Instructor Cheon Saemyung leaned over and whispered into his ear.
"Dean, we scheduled the match to begin at the start of mi-si (1–2 p.m.), and it's already almost mi-si-jeong (2–3 p.m.). How can we allow such disregard for academy rules?"
"Indeed. I believe we should declare him disqualified."
Instructor Yeo Unjin chimed in supportively.
The dean silently exhaled and looked around.
Complaints were beginning to spread due to the delayed duel.
While the event was technically a practical test rather than a mere show, letting the public witness such disorder did no good for the academy's image.
'It can't be helped.'
Juyucheon suddenly rose to his feet.
The murmuring crowd fell silent, all eyes turning to him.
"Today's match is a critical one to appoint the assistant spear instructor for first-years. However, since the participant has yet to arrive, I must regrettably declare—"
"Hold it!"
A thunderous shout rang across the courtyard.
Juyucheon stopped mid-sentence and looked up.
A man stood tall on the roof of the building across the way.
Sabi River?
Juyucheon furrowed his brow slightly as Sabi River leaped down and landed squarely on the duel stage in an instant.
Thud!
Juyucheon's eyes widened slightly.
'That footwork just now…'
It was crude yet strange—an odd movement technique.
The other instructors and students who saw Sabi River were equally shocked.
"What the heck was that? How'd he land there like that?"
"No idea. Even seeing it, I can't figure it out."
"I've never seen a movement technique like that before."
Dean Juyucheon raised his voice to quiet the commotion.
"Silence!"
Once the crowd quieted, he turned to Sabi River.
"Why are you so late?"
"I had an errand to run. My apologies."
Sabi River apologized politely, though his expression showed little remorse.
'Hmm. Was he always this bold?'
Juyucheon was quietly unsettled by the unfamiliar presence Sabi River exuded.
The instructors and students on the platform shared in the confusion over Sabi River's changed demeanor.
"Was he always like this?"
"No, he used to be incredibly mild-mannered."
Meanwhile, Maeng Sondeok stepped forward with a grin.
"A pleasure to meet you! You were so late I thought you'd run off somewhere."
He let out a hearty laugh.
The people around them chuckled as well, the tension finally easing.
Sabi River glanced sideways at Maeng Sondeok.
'So it's him, as expected. Heh.'
He remembered clearly.
When he rushed over after hearing that Yeon Wookyung had been dragged away by thugs, the man in the mask was there—this very man.
And then...
'I got beaten senseless and lost consciousness.'
A memory he had wanted to forget surfaced.
In the past, the moment he saw Maeng Sondeok on the duel stage, he had lost all will to fight.
From the chilling grin and the voice alone, he recognized him as the masked man—and gave up before the duel even began.
From that day on, he was demoted to doing menial tasks around the academy.
But now...
'Everything is going to be different.'
Sabi River smirked and looked at Dean Juyucheon.
"Is that him?"
"Hmm?"
"Is that piece of trash over there really my opponent for the duel?"