Yuuya didn't sleep.
Not because he was scared. Because he couldn't. His heartbeat was syncing with something that wasn't there. Or wasn't supposed to be.
> [New Event Detected: Unregistered Rift Detected – 17.2 meters]
It was floating. Literally floating outside his house. Like a dark hallway drawn into the sky and then left unfinished. A rip in space. A joke from the universe.
And somehow… it was calling him.
He pulled on his jacket, grabbed the iron fire poker he kept beside his bed like a psychopath, and stepped outside like it was a morning jog.
---
The rift was black and purple, swirling, humming softly like a microwave on the verge of exploding. It was low. Streetlight height. And everyone on the block was still asleep.
> [New Dungeon: "The Hollow Door"] [Difficulty: F-Class] [Estimated Completion Time: 32 minutes]
> [Warning: No Class Detected] [Proceed Anyway?]
Yuuya blinked. "I mean. Obviously."
> [Initializing Dungeon…]
The world twisted. The pavement bent. His vision pixelated like someone toggled the graphics settings mid-game.
Then everything went quiet.
---
> [Welcome to The Hollow Door] [Enemies: Lost Shades (x??)] [Objective: Survive. Escape. Remember.]
"…Cool."
The hallway stretched endlessly. Like a school corridor that forgot to stop being built. Doors on both sides. Black mist. The kind of lighting horror games use to remind you you're not the main character anymore.
The fire poker hummed in his grip. Not because it was magical. But because his hand was shaking.
> [Passive Skill: True Learning Activated] [Analyzing Dungeon Environment…]
He crouched and picked up a shard of broken mirror on the ground. It had fingerprints. Human. Recently placed.
> [Memory Echo Imprint Detected – Would You Like to Absorb?]
He didn't answer. The system didn't care.
> [Memory Loaded: A girl screaming. A door closing. A shadow with no face.]
Yuuya exhaled. "I'm not going to die in a rift that sounds like a bad indie horror game."
---
The first enemy came limping out like someone hit the wrong 'load asset' command.
A Lost Shade.
It looked human. But glitched. No mouth. Face smeared like bad photoshop. It moved like lag in human form. And it reached for him.
Yuuya swung the poker.
It passed through.
The shade didn't stop. Didn't flinch. Didn't care.
> [Warning: Physical Damage Null – Use Memory Echoes or Cognitive Strikes]
"Cognitive what?"
> [Processing…] [Suggestion: Recreate memory signature]
Yuuya stepped back, closed his eyes, and remembered the scream from earlier. The door slamming. The fear.
He opened his mouth.
And screamed.
The hallway rippled. The shade staggered. Flickered.
Yuuya didn't stop. He kept screaming until the air bent.
> [Cognitive Pulse Registered – Weak Spot Exposed]
He stabbed the poker straight into the shade's chest. This time, it hit something real.
The shade dissolved.
> [Enemy Defeated – EXP: 9] [Progress: 1%]
"…You've got to be kidding me."
---
Three more shades. Same process. He remembered fragments, then weaponized them.
One time, he laughed at the memory of someone's joke. The laughter warped the shade into a giggling pile of static before he finished it off.
> [New Skill Acquired: Emotional Echo – Tier F]
"You're telling me I just unlocked sarcasm as a weapon."
> [Confirmed. Emotional Echo synced to mental state: Cynicism, Sarcasm, Irony.]
> [Passive Bonus: Inner Monologue now causes minor psychic recoil to hostile echoes.]
---
Halfway through, the dungeon began to change.
Doors started opening.
Behind them? Not monsters.
Just people. Memories. Fragments.
One was a teacher he never had. Another, a dog from someone else's childhood. They stood there, looped in a scene that never ended.
He walked past, not speaking. He knew what they were.
> [Lost Memories – Optional Absorption]
He declined. Too many borrowed thoughts, and he'd forget his own.
---
Final room.
It looked like a janitor's closet. Smelled like bleach and rain.
A single light bulb. And a mirror.
In the mirror: Yuuya.
But older.
Wearing a uniform with a badge he couldn't read. Holding a blade that bent light.
> [Boss Fight: Echo of Potential Self]
> [Class: Unknown – Status: Unrendered]
"…You're joking."
The reflection stepped forward. It moved smoother than him. Stronger. Like it had fought this fight a hundred times.
Yuuya raised his poker. "Let's see what I can learn."
---
It was brutal. The reflection didn't talk. Didn't taunt.
Just moved. Clean. Calculated.
Yuuya was hit. Again and again. He rolled, kicked, screamed. Used every scrap of memory echo he had.
But he was losing.
Until—
> [Overflow Trait Unlocked: System Defier] [Effect: When faced with impossible odds, user can overwrite one rule]
He gasped. "I overwrite… what?"
> [Select Rule to Overwrite:]
1. 'You do not have a class.'
2. 'The enemy is stronger than you.'
3. 'You are not ready.'
He tapped the third one.
> [Rule Overwritten: 'You are not ready' → 'You were made for this.']
Yuuya stood. Taller.
He ran straight at the echo. Dodged. Slid. Landed a strike.
The mirror cracked.
Again. Strike. Memory. Rage. Impact.
The echo bled static.
Final blow. Yuuya stabbed it in the chest with the poker like it was a relic blade.
> [Boss Defeated – EXP +112] [Dungeon Cleared – The Hollow Door will collapse in 90 seconds.]
> [You Have Gained: Title – "Echo Challenger"] [You Have Gained: Class – None] [You Have Gained: Trait – Cognitive Surge]
He walked out as the world reset.
---
The street was quiet again.
The rift was gone.
But Yuuya could still feel it. In his bones. The world was changing.
A message blinked in his vision.
> [New Rift Detected – 7.2 km from location]
He looked up.
The sky cracked a little.
Then it laughed.
He didn't know why. But he laughed too.