D-Class Investigator's First Day
Monday morning at the Northern Branch, the hallway smelled of detergent and the warm hum of printers. I swiped my ID, and the door gave way, letting in a different mix of scents from inside. The conference room carried the mingled aromas of coffee and paper. Team Leader Yoo Mira walked in holding a thin file folder.
"Official documents came down from headquarters. Byun Jihoon, your D-class certification is confirmed."
A brief silence followed. Oh Jaehoon pushed his chair back slightly and grinned. "Whoa, you're exempt now. Completely cleared through paperwork."
Baek Sorin’s eyes widened. "Really? Wow—that’s huge!"
Kang Doyun uncrossed his arms and added, "Now that you’re D-class, no more slacking on reports."
"Thank you." My throat felt a little tight. Team Leader Yoo Mira opened the folder and pulled out the documents. "You’ll also need to sign the salary renewal paperwork next week. Stop by HR when you have a moment."
She straightened the papers, then looked at me. "Jihoon, this is your official promotion to D-class. Congratulations."
"By the way, with your promotion our team’s classification has also been raised. We’re now part of the regular investigation unit, which means we’ll be deployed to dungeons from D-class up to C-class."
The slide changed. "Our first mission is the Pocheon D-04 Swamp Dungeon. Roughly twenty square kilometers—about the size of a township. The upper level is marshland; the lower level is a collapsed waterway network."
"It won’t be over in half a day like E-class dungeons, then."
"Correct. Starting from D-class, missions don’t finish in a single day. And they’re more dangerous."
"Because the regular monsters haven’t been fully cleared?"
"Yes. D-class dungeons are larger with varied environments, so monsters get missed. That’s why we’ll be going in fully equipped—personal weapons and armor sets included."
"What about C-class?"
"C-class covers an entire township. Think the whole Ildong-myeon area of Pocheon City. Stronger monsters appear, and the risk is significantly higher."
"If one of those goes berserk, the township disappears?"
"Even in a berserk state, C-class environmental changes are limited to a one-kilometer radius. D-class is around five hundred meters. Air, water, and ground conditions only shift inside that zone. Once the barrier closes, the spread stops."
"Larger scale means harder to manage."
"These days, some regions deliberately open B-class breaks to secure resources. Maintaining mana circulation improves mana stone extraction efficiency, but the danger rises accordingly. A-class breaks are usually caused by human error—missed reports or misallocated forces. S-class is different. In the early days we lacked the hunter power to close them completely. Now they’ve been converted into managed zones under direct government control. Mana density around them remains high, which is why some B-class breaks are deliberately attached. Abundant resources, but extremely hazardous."
Once the meeting ended, we headed down to the equipment storage. Three mana sensors, power packs, filter masks, drone batteries, and five bombs—one per team member. We checked everything off the list and loaded it into the trunk. From my personal locker I took a composite sword, a set of daggers, and mana-stabilizing gloves. Adding the protective suit and spare battery pack filled the trunk to the brim. The lid closed with a dull metallic click.
"Today we’re only confirming upper-level stability. We’ll head to the lower level tomorrow."
At her crisp voice, the whole team nodded.
The H-Van bounced over the uneven access road. The cases and sensors in the trunk stayed firmly secured, absorbing only the vibration. The steel barricade at the entrance stood half-open, its plates groaning as we passed.
"Approaching the gate. Check your gear."
When the vehicle stopped, the mud at the edge of the water tugged at our boots. The air was already saturated with moisture, and a faint sheen of reflected light rippled across the surface. I set up the mana sensor on its tripod, drove the legs into the ground, and connected the power. The vibration through my palm was steady. The screen lit up, and the stabilization graph slowly settled.
"Calibrating to the internal waterway lines. Jaehoon, fix line one."
Oh Jaehoon organized the cables and extended them to the next line. A short tone sounded from the sensor.
"Line one, western waterway secured."
Fog hung low. Moisture coated every surface, and each step sank into the soft ground. Scanning the readings, my brow furrowed on its own.
"Team Leader, this level of residual mana means the purification wasn’t complete."
"According to the report, the Black Tortoise team finished the first purification yesterday afternoon. If the readings are this high, something must have regenerated inside. The humidity and temperature conditions were probably ideal."
"Mana must be flowing back up from the lower level."
At that moment the water inside the entrance rippled. Three River Crabs raised their claws and scraped against the steel plates. The mud bulged, and two Brown Slimes slid out.
"Sorin, clear the line of sight."
Baek Sorin raised her arm. A thin gust of wind swept the spore dust aside. She shouted, "Wind Blade!"
A sharp current followed the arc of her hand, splitting the slimes’ surfaces. Their insides burst, releasing a fishy stench, while the remaining slime sank back into the mud and lost its shape.
The three crabs leaped at once, metal legs striking the water and scattering droplets. Team Leader Yoo Mira stepped forward and raised her hand.
"Flame Bullet."
Three streaks of fire shot from her fingertips and exploded over the crabs. The water heaved, red heat spreading as their carapaces cracked. Once the flames passed, the three monsters collapsed. Black ash slowly floated to the surface, and for a while only the sound of dripping water remained.
"Area clear."
I approached the water’s edge and examined the overturned River Crabs. Yellow D-class mana stones gleamed between the cracks in their shells. I floated a dagger with telekinesis, slid it into the fissures, and pried them open. Viscous fluid spilled out, revealing the stones. They dropped onto my backpack with a dull thud.
The slime remains had already begun to harden into blue orbs. I gathered them with telekinesis. As the surface solidified, the glow faded.
"Collection complete. Moving to the next sector."
The spore layer beneath the fog stirred again. The water rippled, and the air grew heavier. Three more Brown Slimes and three River Crabs emerged.
"Telekinesis Control."
The flow from my fingertips wrapped around the slimes, lifting all three at once. I reversed the pressure and slammed them into the ground. Mud and slime splattered. Each burst released a stronger stench.
"Slimes neutralized."
As I drew breath, the water surface trembled. Three River Crabs surged upward, metallic claws flashing. I used telekinesis again, pinning their legs into the sand until they stopped struggling.
"Jaehoon hyung."
"Yeah."
"Power sphere."
A blue orb flew in and struck one of the clustered crabs. Electricity crackled outward. The three monsters convulsed simultaneously, then went still.
"Nice, Jihoon! One shot, three kills just because you ranked up?"
"They were slimes. Basically jelly."
"Still, a D-class pulling off a triple kill is basically C-class territory. Did you drink an elixir?"
I felt a twinge of guilt. How did he know? I glanced away and played it cool.
"You drink C-class elixirs too, hyung. I wouldn’t mind one myself."
"Those are for training. Yours didn’t just make your eyes sparkle."
"Come on, it was only three blobs of jelly. Slimes, remember?"
"Good excuse. Next time prove it with crabs."
"Then you turn the electricity off."
"Where’s the fun in that?"
We both laughed as the fishy smell and damp air drifted past.
I floated the overturned River Crabs closer with telekinesis, pried open their shells, and extracted the mana stones. They dropped into my backpack one after another. The remaining slime orbs followed.
"Recovery complete without touching anything. No blood either—nice."
"We’re basically an automated system now."
"My wrists still take a beating. Even when I move the dagger from a distance, my hands keep trying to grip it."
"Old habit. You used to put real strength into your hands."
"Exactly. I use telekinesis but my arms move with it. Can’t break the habit."
"That’s why you’re looking for a mana stone scanner, right?"
"Yeah. If it can pick out only the ones with stones, my hands might finally get a rest."
"Already submitted the request. Once the Investigation Bureau approves it, you’ll get one soon."
"Really? Then maybe my wrists will survive the next mission."
"Protecting Jihoon’s wrists is my top priority."
"Collection complete."
"We won’t log these mana stones in the official record. Consider them personal bonuses."
"Team Leader, should we settle the Chuncheon dungeon from last time together? I haven’t finished processing that one yet—sorry."
"It’s fine. Combine it with this batch."
"Team Leader, you’re the best. I’ll work even harder next time."
"I’ll be sure to note that. All right, let’s wrap up here. We’ll re-enter the lower level tomorrow."
We packed the equipment and walked toward the gate. Light shimmered, the passage opened, and one step later the world flipped. Outside, dusk had already fallen. The van waited. We loaded the gear, the doors closed, and the engine rumbled low. The boundary lights around the gate receded in the side mirror.
Back at the Northern Branch in Uijeongbu. Wet pavement reflected the parking lot lights. We each carried our share of equipment inside.
"That’s it for today. We’ll meet in the conference room tomorrow morning before heading back in. Finish your reports before the meeting. Good work, everyone."
"Yes, Team Leader."
"Get home safely."
"See you tomorrow."
The team dispersed with their gear. I retrieved my bag from the locker, swiped my ID, and headed for the dojo. Cheollyugwan was a fifteen-minute walk away, the heavy bag slung over my shoulder.
When I pushed open the door, Master Han Do-hyun called out immediately. "Jihoon, you’re late again. Miss a day and it’s double."
"Yes, Master."
I removed my shoes, took my place on the mat, and the training began. Two hundred sit-ups, two hundred push-ups, a full lap sprint around the track, then four hundred downward sword strikes with the wooden practice sword. Master Han corrected posture without mercy; any sloppiness meant starting over. The rules were strict—absence or tardiness doubled the next session’s workload, and excuses without proof were not accepted.
After training I returned my sword, put on my shoes, and stepped into the cold night air. My phone showed a new message: [Field Report Schedule Adjustment – Conference Room B, 09:00 tomorrow]. I bought water and a boxed meal at a nearby convenience store, walked the remaining distance to my apartment, and rode the elevator up.
At home I set down my bag, drank cold water, showered, and sat at my desk. Today’s battle replayed in my mind—the first D-class dungeon, the sensations still lingering in my fingertips. In that moment, I knew I had truly changed.