Kugugugugugu────!!!
The vast swamp splits apart.
Between the widening cracks of the swamp, a colossal mountain slowly began to emerge from within.
It looked like a massive earthquake—or perhaps like a volcano erupting.
["Wow..."]
Esther stood there, mouth agape, silently watching the scene unfold.
And she wasn't the only one who had lost her senses.
[Kyaa? Kyaaak!]
[Kieeeek!]
The flying beasts that had been charging at me just moments ago suddenly veered toward the Ark, as if entranced by something.
It was a phenomenon caused by the Wave triggered by Opacum's awakening.
'I definitely need to investigate that phenomenon.'
Why do the Waves occur?
If that puzzle could be solved, it might lead to a way to clear The Defense.
Many users had attempted to tackle that problem.
Some claimed to have reached the edge of the outer world beyond the Ark after endless hardships, while others joined the Church of Morte to uncover the secrets hidden by both the Ark and the Church.
But all of them failed.
The reason behind the occurrence of the wave remained unknown, with only endless speculation running wild.
'That aside...'
While investigating the source of the wave was important, the immediate priority was still the rotting body of Opacum.
A boss stage.
This stage couldn't even be compared to the typical wave events—one mistake here, and the Ark could face total annihilation.
'No room for carelessness.'
Without relaxing for a moment, I stared at the rising figure of the decaying Opacum.
Kugugugugugugu────!
Muck from the swamp clung to Opacum's body and slowly sloughed off.
As it fell away, Opacum's form began to fully reveal itself.
[Guoooooooooooo────!]
The swamp dripped down.
But it wasn't just the swamp that was falling.
It was flesh.
Rotting, decomposing flesh slid off Opacum's body along with the swamp muck.
A decaying body.
And a body that had already decayed.
Esther clicked her tongue at the grotesque spectacle.
["What is that..."]
As if to confirm that Opacum was now fully awakened and in motion, a foul stench began to waft in with the breeze.
The smell of Opacum's rotting flesh.
It wasn't just a rotten stench—it carried toxicity as well.
'...So this is what it's like.'
Of course, this was my first time smelling Opacum's decay directly.
Back when I'd seen it from outside the screen, I'd always equipped a gas mask due to the status effects, and I remember how fast the filters would run out.
'This isn't a stench you can just power through.'
If it were just a foul odor, I could endure it with willpower—but the problem was that Opacum's rotting smell was actually toxic.
Trying to save filters by going without a gas mask would only lead to poisoning, so I quickly put one on.
Splish────!
Splat──!!
The swamp and chunks of flesh sliding off Opacum hit the ground with heavy thuds.
["Ugh... I'm gonna be sick."]
At last, Opacum's rotting body fully emerged, revealing a form resembling a giant lizard.
But unlike ordinary lizards, its overwhelming size and the fact that its entire body was decaying set it apart.
'Here it comes.'
Opacum, now fully awake, took its first step.
Thoooom────!
As the heavy step landed, the swamp churned and a small wave swept across the area.
Kwa-kwa-kakakaka───!!!
Krrrrrrrrng!
'Now.'
With that, the surrounding trees fell, naturally igniting the explosives hanging from them.
Bwooooom────!!!
Using that as a kind of signal flare, the explosives tied to the trees began to detonate.
Kugugugugugugung────!
The first to go off was the TW-742 Thermobaric Bomb planted above Opacum's head.
Kakakakakakang!!!
[Gwoooooooo!!!!]
Opacum's head reeled.
That's how powerful the blast was.
'That's just the beginning.'
The TW-742 Thermobaric Bomb was merely the opening act.
To prove it, a massive explosion was followed by a chain reaction of blasts.
The next explosion targeted Opacum's eyes—an NA-44 Napalm charge.
Fweeeeeeee───!!
Pop! Popopopop!
Like fireworks, sparks began bursting, then rained down on Opacum's eyes.
[Gyaaaaaaaaaaaaah───!!!!]
A scream unlike any before.
Even for Opacum, with its rotting body, an attack to the eyes was effective.
Thooom───!!
Thoooom────!!!
Opacum, now rampaging wildly, began thrashing through the surrounding trees.
And of course, that served as another trigger for more explosives.
Boom!!
Bwooooom───!!!
TNT Type 778.
TOLMAN15.
RDX-14.
One after another, massive explosives detonated in sync with Opacum's movements.
All of this was carefully planned in advance, accounting for its path and the chain reactions caused by each explosion.
[Gwooooooooo─────!!]
Opacum's horrifying shriek echoed.
But the explosions didn't stop.
On the contrary—they grew stronger.
Krrrrrrrrrrrng!!!!
Opacum's body lurched violently.
It had stepped into one of the traps I had laid.
And inside that trap, naturally, were more explosives.
Boom!
Bwooooooom────!!!
Explosion, explosion, and another explosion.
To an outsider, it might have looked like we'd gathered every ounce of gunpowder in the world.
[Kyaaaaaaaaaaagh!!!!]
A terrible screech, like metal being scraped, rang out in all directions.
Still, the explosions didn't cease.
Krrrrrrrrrng─!!!!!
Amid the continuing blasts, the staggering Opacum stepped into another pit and finally collapsed.
BOOOOOOOOM────!!!!
When a giant monster of Opacum's size falls, it's a calamity in of itself.
The massive swamp once called Opacum's domain was now losing its former shape—because of its master.
[Ghak! Gahak...!!!]
Opacum thrashed and howled.
Watching this, Esther clicked her tongue again.
["Eww... It's still alive?"]
Despite using such a ridiculous number of explosives, we hadn't managed to kill Opacum.
It couldn't be helped.
This was a BOSS of a boss stage.
If it were that easy to take down, it wouldn't hold that position in the first place.
'Still, that doesn't mean it's unaffected.'
Anyone could see Opacum's current state wasn't good.
Its entire body was scorched and blackened from the explosions, and its eyes were still burning from the NA-44 Napalm Bombs and the Type-88 Incendiaries.
Even if those didn't blind it completely, they were enough to inflict significant damage.
'In that case, I guess it's time for me to move.'
Until now, I hadn't made a move myself due to the precisely timed explosions, but now that we were running low on charges, it was a different story.
I switched the Ark-34 automatic conversion rifle to Railgun mode.
Zzzzzzt...
Clack, clack.
Then I took aim squarely at Opacum's forehead.
'One shot, to start.'
Powerful energy gathered at the Railgun's muzzle, sparking wildly.
Tzzzt─
Tzztzzt!!
But I didn't stop there.
"Esther, back me up."
["...There?"]
"Yeah."
True, combining ether with a Railgun was likely something even Esther hadn't experienced.
["That might be a little hard..."]
"You can do it."
["...Is that a compliment or what."]
With that, the ether began to surge violently.
[Should I kill it?]
[Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it. Kill it...]
[Let's kill it—kill it—]
The ether, now infused with pure murderous intent toward the monster, condensed at the muzzle of the Ark-34 Railgun.
Everything was ready.
All that was left was to pull the trigger.
Shreeeeeeeeeeeeeeeeeeek─────!!
A straight beam of destruction shot toward Opacum's forehead.
* * *
The red warning light that signals a wave continued to blink.
It was the soundless siren that symbolized the Ark itself.
"Hurry, everyone!"
"It's a wave!"
Because it was a wave occurring exactly as scheduled, the soldiers of the Ark moved in perfect coordination.
All equipment checks had already been completed—what remained was deployment to the frontlines.
Screech, screeeech...
Heavy machinery transported large weapons one by one onto the Ark's fortress walls.
It would've been ideal to have them deployed before the wave hit, but due to tight inspection schedules, there had been no choice.
In fact, even this last-minute deployment was something of a miracle.
Lieutenant Colonel Banol stood atop the fortress wall—unusual for him during a wave.
That was because he felt a sense of unease he couldn't shake.
'The recon drones' range has shrunk again.'
The Ark regularly dispatched recon drones to the outside.
But due to the proximity to Mount Noah, the drones' range was severely limited, and the data they could transmit was minimal at best.
Lately, that limited range had been shrinking even further.
Especially in the southeastern sector of the Ark.
'I hope it's nothing serious...'
But unfortunately, Lieutenant Colonel Banol knew better.
These ominous feelings usually turned out to be disturbingly accurate.
That was why he had taken the risk to come to the frontlines in person—to respond as swiftly as possible if anything did happen.
Darkened skies loomed beyond the horizon, a mass of gathering storm clouds.
Any soldier of the Ark would know—those weren't ordinary clouds.
Each of them was a mass of flying beasts and monsters forming the blackened swarm.
That was why the soldiers didn't let down their guard for even a moment as they stared toward the frontlines.
Thoom—
Kugugugugu───
Then came the tremors.
To the soldiers of the Ark, this too was all too familiar.
It was the most obvious sign that a vast army was approaching from beyond the horizon.
'Something's different.'
Lieutenant Colonel Banol could feel a strange dissonance rising from beyond the horizon.
That dissonance grew stronger the more he focused on the southeastern direction of the Ark.
'Something is happening out there.'
And then—
Thooom───!
BOOM!!!!
A distant tremor was felt.
But this tremor was distinctly different from the usual advance of enemy forces.
It was much deeper, heavier.
'...No way.'
Just as a thought began to form in Banol's mind, something began to emerge from the far southeast of the Ark.
BOOM!
THOOOOOOOOOOM───!
"That's..."
Banol's face turned pale.
And with good reason.
For a monster to be visible from near the horizon, dozens of kilometers away, could only mean one thing.
A colossal monster.
It was approaching the Ark.