The Gate opened beneath Blackstone Citadel at dawn.
There was no explosion, no dramatic roar. The stone street simply cracked apart, as if something beneath the world had finally decided to breathe. Pale blue light seeped through the fissures, spreading outward in a perfect circle.
People noticed instantly.
Merchants abandoned their stalls. Guards backed away with tight expressions. No one screamed—but no one stayed close either.
> [Dungeon Gate Detected]
[Location: Lower Ward – Trade Circle]
[Estimated Rank: D]
"Inside the walls…" someone murmured.
That was bad.
A D-rank dungeon appearing inside a Citadel meant failure—either a delayed response or an underground rupture no one had detected in time.
Leon Mercer stood at the edge of the plaza, half-hidden behind a stack of cargo crates. He pulled his hood lower and watched the light with narrowed eyes.
Blackstone Citadel loomed behind him, its massive walls layered with reinforcement runes and watchtowers. It was a city built to survive the Age of Gates.
People like Leon survived by not being noticed.
---
Hunters arrived quickly.
Guild hunters.
Their footsteps were confident, armored boots striking stone in unison. Cloaks bore insignias woven with mana thread, glowing faintly as the System recognized them.
Leon's gaze lingered on one symbol in particular.
A black pickaxe crossed over a vein of silver.
Iron Vein Guild.
Mid-tier. Efficient. Known for low casualty reports—mostly because they used disposable manpower.
Leon turned away.
Too late.
"You there."
A handler's voice snapped like a whip.
Leon froze, then slowly turned.
The man wore light armor and a contract slate strapped to his arm. His eyes swept over Leon's worn gear and stopped at the faint System mark hovering above his shoulder.
> [Hunter Rank: F]
"Dungeon experience?" the handler asked.
Leon hesitated for half a breath, then nodded. "Subterranean ruins. Low-tier."
That was technically true.
"Good," the man said without interest. "You're carrying. Don't slow us down."
A contract rune flared briefly against Leon's wrist.
Binding. Temporary. Cheap.
Leon clenched his hand as the rune faded.
Another job where dying was an acceptable outcome.
---
The Gate stabilized within minutes.
The blue light thickened, forming a clear boundary. When the raid team stepped through, the city vanished instantly.
Stone replaced stone—but older. Wetter. Carved by hands long dead.
> [Dungeon Entry Confirmed]
[Dungeon Type: Subterranean Ruins]
The air was cold and heavy, tasting faintly of iron.
Leon exhaled slowly.
His ability window slid into view without being summoned.
A circular frame. Three cards rotating endlessly.
Blue Card
Red Card
Gold Card
No numbers.
No percentages.
Just effects burned into his mind since the day he awakened.
Restore.
Explode.
Stun.
A gambler's power.
A bad joke, according to the System examiner.
---
"Formation," the raid leader ordered.
Iron Vein moved smoothly—two melee in front, shield bearer center, casters behind. Leon took his place at the rear, pack already heavier than it should've been.
They didn't get far.
Stone scraped against stone.
Red text flickered into existence.
> [Stone Gnawer – D Rank]
The creature crawled out of a side tunnel, its body a fusion of jagged rock and bone. Another followed. Then three more.
"Engage."
Magic lit the corridor. Fire scorched stone. Steel rang.
Leon stayed back.
Always back.
---
The fight was clean. Efficient.
Too clean.
Leon watched the shadows more than the monsters.
That habit had kept him alive.
He saw it a heartbeat before it happened.
A Stone Gnawer slipped along the wall, bypassing the frontline entirely. Its eyes locked onto the weakest presence in the room.
Him.
"—!"
Leon's body moved before fear could settle in.
Lock.
The rotation stopped.
Gold Card
The card formed between his fingers—solid, warm, humming with restrained power.
Leon flicked his wrist.
The card flew straight and true, striking the monster between the eyes.
The Stone Gnawer froze mid-lunge, limbs locked in place.
"Backline clear!" someone shouted.
A sword flashed.
The creature shattered.
Leon's breath came out in a sharp exhale.
The card dissolved into light.
Then—
> [Card Dealing – Proficiency Increased]
[Gold Card: Stun Duration +0.2 seconds]
Leon's eyes narrowed.
Again.
Not chance.
Progression.
---
They moved deeper.
The dungeon twisted downward, corridors narrowing. Monster encounters became more frequent.
Leon used his cards sparingly.
A Red Card when enemies clustered too tightly—exploding with controlled force.
A Blue Card when his stamina dipped too low—sending a cool surge through his body on impact.
Each use tightened a band around his skull.
Mental load.
No mana bar. No warning until it was too late.
Just pain.
---
Half an hour in, things went wrong.
A caster misjudged timing.
A Stone Gnawer—larger than the rest—burst from below, erupting from the floor itself.
The shield bearer stumbled.
"Mercer!" the raid leader snapped.
Leon didn't hesitate.
He watched the rotation.
Blue… Red … Yellow …
Too slow.
Leon clenched his teeth.
Force Lock.
Pain exploded behind his eyes as the system resisted.
🟡 Gold Card – Forced Lock
Blood ran from Leon's nose.
He threw the card.
The stun landed.
But it shattered early.
"—What?!"
The monster roared and lunged again.
Leon's vision blurred.
🔴 Red Card
The explosion detonated at close range.
Leon was thrown backward, slamming into the wall. Pain flared through his ribs.
The monster collapsed, smoking.
Silence followed.
---
Leon slid down the stone, gasping.
A warning flickered weakly.
> [Warning: Mental Load Critical]
The raid leader turned and finally looked at him.
Not with gratitude.
With interest.
"…You're better than the report," he said.
Leon wiped the blood from his face and forced himself to stand.
He recognized that look.
Reassessment.
In this world, that was dangerous.
---
The corridor ahead widened.
A massive door loomed in the darkness.
The boss room.
Leon's cards continued to rotate—slower now, but steadier.
In a world where power was fixed and ceilings absolute—
His ability wasn't strong.
It was flexible.
And flexibility broke rules.
Leon tightened his grip and stepped forward.
The Dealer's hand was just getting started.