The cold air clung to Riku's skin like a damp shroud. Each step he took echoed along the stone corridor, swallowed quickly by the oppressive darkness. The only source of light came from faintly glowing crystal veins embedded in the walls flickering, like a dying flame.
He clutched the small black book tighter in his hand.
His Class Book. The only thing the world had allowed him to keep.
"I'm alone… in an SS-Rank dungeon… with a class that can't even punch a slime."
Riku's breath misted in front of him. It wasn't just the chill in the air. It was the weight of fear and helplessness pressing down on his chest. But fear wasn't new to him. Being overlooked, underestimated, mocked that had always been his world.
But this? This was worse. This was abandonment.
He opened his book with a slow breath. As the pages turned, a translucent screen emerged in the air before him.
---
[Observe: Active]
Target: Red Slime
Movement: Slow. Circular attack patterns.
Weakness: Fire. Freezing.
Note: Lacks a central brain. Reacts to sound and vibration.
---
A faint squelch echoed down the corridor.
Up ahead, the red slime squirmed slowly across the floor like a living puddle of molten jelly. Harmless-looking, but Riku knew better. The acidic slime could melt through flesh in seconds.
There were no HP bars. No battle menus.
This wasn't a game. But it wasn't quite real life either.
It was something in-between.
Riku studied the floor and walls, his mind already moving faster than his fear. His eyes darted to a narrow ledge near the right wall and a jagged rock beside his foot.
"If I bait its jump and sidestep at the right moment… I might be able to trick it into falling."
He took a deep breath, then tossed the stone.
The slime twitched.
It lunged, exactly as predicted.
One step left. Two steps back.
The slime's momentum carried it too far, and with a wet plop, it vanished into the pit beside the corridor.
---
[Target Defeated: Red Slime]
[Skill Detected: Acid Body (Passive)]
[Archive Slot Full (1/1)]
[Record this skill? Y/N]
---
Riku pressed "Yes."
A moment later, another window appeared.
---
[Skill Recorded: Acid Body]
Type: Passive
Description: Produces corrosive liquid from user's skin.
Note: Cannot be activated directly in current condition.
---
"…Even recorded like this, I can't use it yet."
He closed the book and let out a shaky breath. But instead of despair, something flickered in his eyes determination.
"If I can record skills… and eventually modify them…"
That was his only path forward.
To survive, he had to think differently.
◆◇◆
Three days passed.
Riku moved like a ghost through the shadows of the dungeon, dodging monsters, mapping the terrain, and analyzing every encounter. He recorded their behaviors, their strengths, their weaknesses. He sketched strategies in the margins of his Class Book, sometimes redrawing the same diagram ten times until the pattern clicked.
He had no sword. No magic. No divine power.
But he had his mind.
He survived on bitter roots and water pooled from the cavern walls. His clothes were torn. His body was bruised. His legs ached from lack of rest.
But his eyes? Sharper than ever.
Then, at last, he arrived at a massive stone door etched with runes that shimmered faintly in the dark.
---
[Boss Room Detected]
[Target: Ancient Golem – Lv.48]
[Recommended Party: 5 members, Lv.30+]
---
Riku stared up at the towering doorway as it creaked open slowly, as if welcoming him.
Inside stood a golem the size of a two story building. Ten meters tall. Broad like a fortress. Its body was made of jagged stone slabs, held together by glowing crimson energy. Its chest pulsed with a blinding red core, and its expressionless face watched him with mechanical coldness.
---
[Observe: Active]
Target: Ancient Golem
Movement: Slow but powerful. Area attacks.
Weak Point: Chest (glow intensifies while charging energy)
Skills:
– Ground Smash
– Shockwave Aura
– Energy Core Overload
[Skill Noted: Energy Core Overload]
Description: Concentrates all core energy into one final attack, destroying target and self.
---
Riku's pulse quickened.
"If I can trigger that final skill and dodge it… he'll destroy himself."
But there was a problem.
His Archive Slot was full.
Only one skill could be recorded at a time.
He opened the skill menu.
---
[Stored Skill: Acid Body (Passive)]
[Replace skill? Y/N]
---
His hand trembled slightly as he pressed "Yes."
Acid Body vanished from his Archive.
A new skill took its place.
[Skill Recorded: Energy Core Overload]
---
The golem stirred, footsteps like thunder.
Riku ran behind a pillar and hurled a stone at one of the glowing wall crystals. It shattered with a sharp ping. The sound echoed wildly through the chamber.
The golem turned toward the wrong direction.
Another stone. This time at its foot.
Crack.
A fracture split along the golem's ankle.
Its red core flared.
---
[Skill Activated: Energy Core Overload]
[Countdown: 5 Seconds]
---
Riku ran, diving behind another broken column.
The golem's body lit up like a furnace.
And then
BOOM.
A deafening explosion ripped through the room. The shockwave knocked Riku off his feet. Rubble rained from above. For a moment, all he saw was red light and smoke.
Then silence.
He coughed and opened his eyes slowly.
The Ancient Golem was gone. Nothing remained but shattered stone and a glowing blue crystal floating gently in the air.
---
[Evolution Trigger Item Acquired: Soul Code Fragment]
[Skill Evolution: Archive → Rewrite Protocol]
---
[Rewrite Protocol: ACTIVE]
New Functions Unlocked: Modify recorded skills
– Combine two or more recorded skills
– Adapt skill based on user's condition
---
Riku stared at the screen. His chest heaved, knees shaking. But this time… he was smiling. The system had acknowledged him. Not with strength. But with strategy. He stood slowly, gripping his book like a weapon.
"From the lowest class… I'll rise to the top."
◆◇◆
Elsewhere, in the royal capital of Arzallia...
Leonhardt the golden-haired student with the Class: Holy Hero stood in a lavish training hall, sword resting against his shoulder.
A knight rushed in with a report. "Sir Leonhardt. We've received word… The SS-Rank dungeon's guardian has been destroyed."
Leonhardt raised an eyebrow. "That dungeon? Wasn't that the disposal zone for the 'unqualified'?"
He smirked faintly.
"Interesting. If that trash survived… I'd like to meet him again."
---
Riku Aizawa had been thrown away as worthless.
But he would rewrite that judgment, one strategy at a time.
One monster at a time.
One world-breaking move at a time.