The massive underground structure stood silently beneath the cliffs like the remains of something the world itself had tried to bury.
Dark stone pillars surrounded the entrance in uneven circles, many broken or half-collapsed with age, yet faint crimson lines still pulsed beneath their surfaces like veins carrying life through a dead body. Moss and twisted roots crawled over parts of the structure, but they could not fully hide the unnatural design beneath.
Nothing about it felt ancient in a normal way.
It felt abandoned.
There was a difference.
Ayan stood near the edge of the cliff overlooking the structure below, the cold wind brushing against his dark cloak while his eyes remained fixed on the enormous circular entrance descending into darkness beneath the earth.
The deeper he looked—
The more uneasy he felt.
Not fear exactly.
Recognition.
Like the place itself already knew he was here.
The crystal inside the pouch at his side pulsed faintly again.
Ayan immediately noticed.
"…You feel it too."
Aelira stood beside him quietly.
"…The network is reacting to your presence."
Ayan frowned slightly.
"…That's becoming a really bad habit."
The faint vibration beneath the ground continued steadily now, subtle enough that ordinary people likely would never notice it. But after everything he had experienced—
Ayan could feel it clearly.
Something beneath the structure was active.
Watching.
Waiting.
A long silence settled between them as they observed the entrance below.
Then Ayan finally spoke.
"…How deep do you think this goes?"
Aelira's crimson eyes remained fixed downward.
"…Far deeper than this world was meant to allow."
The answer immediately bothered him.
"…That sounds ominous."
"…It is."
Ayan sighed quietly.
At this point he had stopped expecting reassuring answers from her.
Still—
His thoughts remained focused.
Because the moment they stepped inside—
Things would change.
Until now they had been chasing traces left behind by the network.
Fragments.
Corrupted creatures.
Regional distortions.
But this—
This was the source infrastructure itself.
A direct path beneath the world.
And somehow—
Ayan doubted the things waiting below would resemble ordinary monsters anymore.
The wind shifted suddenly across the cliffs.
Aelira's gaze narrowed slightly.
"…We're not alone."
Ayan's hand immediately moved toward his sword.
The forest above the cliffs rustled softly.
Then footsteps emerged from the trees behind them.
Several figures stepped cautiously into view wearing dark traveling cloaks over light armor, weapons visible at their sides. Adventurers.
Five total.
Ayan recognized the guild insignia stitched faintly across their gear immediately.
The group froze slightly after noticing him and Aelira standing near the cliffside.
Then the man leading them relaxed marginally.
"…So someone else found this place first."
He looked around his late twenties, tall with short brown hair and sharp gray eyes. A long spear rested against his shoulder while several scars crossed the exposed skin near his jawline.
Behind him stood:
- a red-haired female archer,
- a heavily armored shield user,
- a young mage carrying several crystal charms,
- and a quiet dual-blade fighter watching everything carefully.
Experienced.
Not random mercenaries.
Ayan's eyes narrowed slightly.
"…Guild adventurers?"
The spear wielder nodded once.
"Silver-ranked investigation team."
His gaze shifted briefly toward the underground structure below.
"We were tracking corrupted monster activity through this region."
Then his eyes returned toward Ayan and Aelira.
"…Looks like we found the source."
Ayan exchanged a quick glance with Aelira.
Interesting timing.
The spear wielder stepped closer slowly.
"…You two alone?"
Ayan answered calmly.
"Yeah."
The man stared at them for several seconds, clearly evaluating.
Probably confused.
Because from appearances alone, Ayan looked too young for this kind of place.
And Aelira—
Well.
People usually reacted strangely to her even without understanding why.
The red-haired archer folded her arms slightly.
"…You're adventurers?"
Ayan nodded once.
"Recently registered."
That answer visibly surprised them.
The mage blinked.
"…Recently?"
The armored man muttered quietly.
"…And they came all the way here?"
Ayan ignored the reaction.
Instead his eyes shifted toward the underground structure again.
"…You know anything about this place?"
The spear wielder's expression became more serious immediately.
"…Only rumors."
He lowered the spear slightly.
"Several guild teams disappeared investigating this region during the past few months."
"…Corrupted creatures kept appearing nearby."
"…Then the distortions started."
Ayan's chest tightened slightly.
So even the guild had already noticed something larger happening.
The dual-blade fighter finally spoke for the first time.
"…The guild believes there's an underground nest connected to the evolving monsters."
Nest.
Ayan almost grimaced internally.
If only it were that simple.
The spear wielder looked toward him again.
"You found anything?"
A brief silence followed.
Ayan thought carefully.
How much should he reveal?
The network.
The previous Earth visitors.
The underground structures.
No.
Too dangerous.
Too unbelievable.
So instead he answered partially truthfully.
"…The corruption underground is connected."
"…And the creatures are changing faster near this structure."
The adventurers exchanged uneasy glances immediately.
Because they had clearly already suspected something similar.
The red-haired archer looked down toward the entrance below.
"…Then we destroy whatever's inside."
Ayan's eyes narrowed slightly.
Destroying it wouldn't be simple.
Not after what he had already seen.
The crystal pulsed again faintly against his side.
Almost like a warning.
Aelira suddenly spoke quietly beside him.
"…Something is moving."
Everyone immediately stiffened.
The ground beneath the cliffs vibrated softly.
Then again.
Stronger this time.
The armored adventurer cursed quietly.
"…Underground?"
Ayan's instincts sharpened instantly.
No—
Not one thing.
Multiple.
The vibrations spread rapidly beneath the earth surrounding the structure below.
The mage's face paled slightly.
"…There's a lot of them."
Then—
The entrance pulsed crimson.
Every line across the underground structure illuminated simultaneously.
And from deep below the earth—
A sound echoed upward.
Not a roar.
Not a scream.
But countless distorted voices layered together unnaturally.
The adventurers froze completely.
Ayan's chest tightened.
Because somehow—
The voices almost sounded human.
The crimson lines across the structure pulsed brighter.
Then the massive entrance slowly began opening wider on its own.
Darkness descended endlessly below.
Cold air surged upward from the depths beneath the world.
And somewhere far below—
Something had realized they arrived.