When the Sky Splits

The clock hands on the classroom wall were about to reach 12:30.

Fourth period, Mathematics II.

The only sound was the elderly math teacher writing formulas on the blackboard, his chalk tapping out a dry rhythm.

His voice was faint, like a Buddhist sutra heard from far away, and seemed to reach no one.

"… Now, if we apply this quadratic formula…"

The classroom atmosphere had stagnated like rotten water.

Some students had their heads on their desks sleeping, others stared vacantly at the lead-gray sky outside, still others pressed their temples as if fighting headaches.

The unseasonable humidity and the unpleasant static electricity clinging to their skin.

A suffocating feeling as if the entire world had been sealed inside a massive pressure cooker was crushing our lungs.

(… Ten more seconds.)

I kept my textbook open while counting down in my mind.

The Mana Core in my chest, right beside my heart, was pulsing violently like an alarm.

The spatial distortion coefficient had breached critical point.

It's coming.

5, 4, 3…

Outside the window.

The overcast sky began glowing red-black from within.

That light, which should have been invisible to ordinary eyes, now physically possessed mass, scorching the air and shimmering like heat haze.

2, 1…

Ding-dong, dang-dong—

The lunch break chime rang out.

That peaceful, everyday melody was the signal for the end of everything.

—CRASH!!

Drowning out the chime came a high-pitched sound that tore at eardrums, like every piece of glass in the world shattering at once.

"—What!?"

"Wh-what was that!?"

The drowsy students snapped their heads up as if jolted.

The shock wasn't just sound.

The atmosphere vibrated violently, the classroom windows rattled and screamed, and several shattered, unable to withstand it.

"Kyaaaah!"

"Earthquake!? What!?"

Flying shards. Screams.

But the true terror came after.

"Look! The sky!"

A male student by the window shrieked in a cracking voice.

Everyone's gaze was drawn outside.

There lay a hellscape beyond imagination.

The sky had split.

Not a metaphor. Literally, the blue dome of the sky had massive cracks running through it.

Lightning-like jagged scars spread from the zenith toward the horizon, countless in number, and from those gaps, a murky purple-black aurora spewed forth.

Pieces of sky were flaking off, dissolving and vanishing before reaching the ground.

Beyond those cracks loomed an ominous red moon never seen before, and a chaotic otherworldly sky.

"N-no way…"

"A movie shoot…? Not CG?"

"No, what is that, it's scary, so scary!"

The classroom instantly descended into panic.

Girls crying and screaming, boys pointing trembling phones, the teacher collapsing onto the podium with weak legs.

Against a scene beyond comprehension, human reason was useless.

Their brains rejected reality, falling into paralysis.

RUMMMMMBLE…!!

As if to pile on, an ominous rumbling rose from beneath our feet.

Not horizontal shaking. Not vertical either.

A nauseating vibration as if space itself was creaking, as if the shape of the world was being rewritten.

I remained seated, calmly looking down at the schoolyard through the window.

The asphalt of the grounds was undulating as if alive.

The steel soccer goal twisted like spun sugar. The old cherry tree uprooted and toppled.

And in the center of the schoolyard.

Where the assembly platform had been, the ground bulged upward as if exploding from within. In the next instant, it transformed into a massive sinkhole.

BWOOM!

Like the gaping maw of a monster, a huge hole roughly fifty meters in diameter formed.

The bottom wasn't visible. From it, black fog carrying the stench of rotting flesh and iron rust gushed upward with tremendous force.

A Dungeon Gate.

A bridgehead of invasion connecting the otherworld to this world.

"KYAAAAAAH!!"

"Run! The schoolyard collapsed!"

"The exit! Get outside!"

Someone's scream triggered complete hysteria across the class.

Knocking over desks, kicking chairs aside, students rushed toward the hallway door, each trying to be first.

The teacher's "Calm down" was drowned out by the uproar and reached no one.

The usual school caste, human relationships. All of it collapsed. Only the animal instinct to survive dominated the classroom.

In that pandemonium.

Only I sat quietly at my desk.

"… Right on time."

I turned my gaze sideways.

The hard-type "fishing rod case" I'd propped against the wall by the window.

About two meters long.

After arriving first thing in the morning and hiding the massive survival backpack in a locker, I'd kept this one at hand.

I gripped the case handle tightly.

The hard texture.

And through the case, the heavy mass of iron I could feel.

A 22mm diameter deformed rebar.

Procured from a home improvement store's materials section and sharpened night after night at the riverbed. My crude partner.

Not yet. I wouldn't draw it yet.

It wasn't time.

"Kurose! What are you doing, let's get out of here!"

Sakaki shouted at me while being jostled by the crowd.

His face was deathly pale, his expression desperate.

But I shook my head.

"Run? Where to?"

I pulled the fishing rod case closer, stroking its cold surface affectionately.

Through the window, from within the black fog, I could see countless "glowing eyes" peering this way.

The hungry gazes of the goblins.

"—Guests have arrived. We should welcome them properly."

I grinned.

That smile wasn't one of an ordinary high school student.

It was the fierce grin of an S-rank adventurer who once dominated battlefields in another world.

The everyday had ended.

My time had come.