As soon as the sirens blared, Lieutenant Colonel Banol's office instantly turned into a war zone.
"Grade-1 situation. Have the extermination personnel returned? ...Close the gate as soon as they're back."
Lieutenant Imosha gave orders without a single care that this was a superior officer's office.
Lieutenant Colonel Banol also didn't seem to mind and rose from his seat.
"I'll be off, then... Everyone, do your part."
Leaving those words behind, Lieutenant Colonel Banol walked out of the office.
Of course, there was no one left standing idly in the office after he left, and everyone moved at once.
"Lieutenant, I'll come with you."
"You just got back from a mission, didn't you? Are you sure you're okay?"
"I'm fine."
"Then let's go."
The conversation between Lieutenant Imosha and Hildegard was brief, as the situation was urgent.
"I'll come too."
Naturally, I joined them.
Since I'd already made up my mind to participate in the battle, it was more convenient to head to a familiar face than wander around getting into skirmishes elsewhere.
"...Are you coming with us?"
"Yes."
Lieutenant Imosha looked slightly surprised but soon nodded.
Ark didn't have the luxury to turn away anyone willing to help in this situation.
"Understood. Let's move. If you're helping, Carl, it'll be a big support."
Our destination was the Red-17 Gate.
It was the area Lieutenant Imosha managed as the gate administrator.
"Hildegard, return to your squad."
"Understood."
With that, Hildegard left, and Lieutenant Imosha turned to me.
"Sorry, but we'll have to split up from here."
"Don't worry about it. Just do as Lieutenant Colonel Banol instructed."
"My duty, huh... Yes, you're right. Then, I'll be on my way."
Lieutenant Imosha gave a slight nod before moving out in earnest.
I was left alone for a moment, but it didn't matter.
This scene was far too familiar to me.
'The only difference now is that I'm not affiliated with any group.'
Originally, I would have been assigned to a company, platoon, or squad to carry out specific tasks, but I didn't belong anywhere now.
If anything, I had the vague title of an honorary citizen of Ark.
Still, I didn't feel out of place among them, likely because I was wearing one of Ark's standard protective suits.
"Hurry up!"
"This way!"
Inside Ark, everyone moved with frantic speed, but there was no sense of chaos.
After experiencing countless waves, Ark's soldiers had become seasoned enough to maintain order even in emergencies.
"Ugh... Uugh..."
Of course, not every soldier was entirely free from fear.
Some of the newest recruits—those who had just shed their trainee status—were visibly trembling.
They belonged to the batch just above Hildegard and Kurilta's class.
'Such types inevitably fall into one of two categories: either they overcome their fear or they fall on the battlefield.'
In the past, those with weak resolve would have been filtered out during training.
However, due to Ark's dire manpower shortage, the graduation standards at most training centers had been significantly relaxed.
The elite soldiers that Ark once produced—who were practically iron-willed—were now drafted even if they had minor disabilities.
Given the circumstances, it was actually surprising that there weren't more recruits succumbing to fear ahead of the wave.
'Now that I think about it... wasn't that guy stationed at Gate 19? If he gets swept up and dies in the wave, that'll be troublesome.'
Among Ark's recruits, there were a few with high growth potential despite being raw and unpolished.
One of the most peculiar among them was the cowardly Bell.
Thanks to her distinctive traits, she had great potential for growth, but she was so weak in the early stages that she could easily die if left unattended.
'I should check on her if I get the chance.'
Although it was important, there were more pressing matters at hand.
I climbed the ramparts and looked out at the scenery beyond.
"Current distance: approximately 7 km!"
"They're almost within range!"
Countless black dots surged over the horizon.
Grrrrrrrooooaaar!
Kaaak, Kaaaak!
Shiiii... Shishisik...
All sorts of grotesque roars echoed from afar.
[It's coming...]
[Run away. Run away. Run away. Run away. Run away. Run away. Run away. Run away. Run away. Run away. Run away. Run away.]
[Ah... Aaaaah...!!!]
Even the ether beside me was trembling.
It was both a strangely familiar and utterly alien sight.
"Close the gate!"
It seemed the extermination personnel had all returned, as the Red-17 Gate, which had been briefly open, was now completely sealed.
The entire area shifted into full combat readiness.
"6 km!"
Lieutenant Imosha, now positioned atop the central wall of the Red-17 Gate, shouted in response to a soldier's report.
"Red-17 unit, prepare for battle!"
At her command, a resolute determination filled the soldiers' faces and movements.
Clack, clack—
Guns and heavy weapons were loaded in sequence, and the soldiers fixed their gazes on the horizon.
Though it was still technically 6 km away, considering the speed of the beast horde, it might as well have been right at our doorstep.
"5 km!"
Before long, the distance between the advancing beast horde and the Red Line frontline had dropped below 5 km.
Considering that the other lines had already started shelling, there was no more time to wait.
"Attack!"
As soon as Lieutenant Imosha gave the signal, the firepower of the Red-17 Gate Defense Force began pouring toward the approaching beasts and monsters on the horizon.
Fwoooosh─────!!
The opening salvo was a missile tracing an arc through the sky.
I didn't know what it was loaded with yet, but there was no need to wonder.
I would find out soon enough.
Kwakakakakakakang───!!!
The powerful thermobaric blast of the JD-074 struck down, and a massive crimson mushroom cloud blossomed above the heads of the beast horde advancing toward the Red Line front.
From the outside, it looked like overwhelming firepower that could wipe out the beasts in one go, but none of the soldiers of the Red-17 Defense Force shouted in triumph.
They already knew.
This was just the beginning.
As if to prove that point, it wasn't long before beasts and monsters started emerging one by one from the rising mushroom cloud.
[Grrrr...]
[Kyaoooooo!!!!]
[Kak, Kaaaak!]
Even though they were all burned and charred from the heat blast, the beasts and monsters that had survived the direct explosion remained standing.
Some of the stronger ones had even taken the full brunt of the JD-074's thermobaric explosion and still didn't die.
'As expected.'
Among beasts and monsters of a certain level, some species with exceptionally tough exoskeletons could withstand overwhelming firepower like that.
To eliminate those creatures, one had to either target their weaknesses or use even greater firepower.
"They're coming!"
That was the beginning.
Taking the mushroom cloud from the thermobaric explosion as the signal, the firepower of the Red Line Defense Force was unleashed.
Tat-tat-tat-tat-tat───!!
Bang! Boom! Booooom!
It was also a sign that it was time for me to step up.
Of course, since I wasn't an Ark soldier, I didn't have to follow the commander's orders.
But I had to remember that being here was purely due to the consideration of Lieutenant Colonel Banol and Lieutenant Imosha.
That was why I had waited for Lieutenant Imosha's attack command before acting.
Click─
The Ark-15 anti-materiel sniper rifle roared to life.
My target was a Grade-2 Monster Species: The Mutated Quetzalcoatl.
True to its classification, the beast had survived a direct hit from the JD-074 thermobaric explosion thanks to its tenacious hide and life force.
'But it's definitely weakened.'
The tough, leathery skin had been torn and tattered by the blast.
Moreover, the acrid smoke rising with every breath proved that the Mutated Quetzalcoatl's lungs had been completely scorched.
In other words, it was significantly weakened.
Bang─────!
There was no need for a suppressor.
This was the middle of a battlefield where noises and explosions filled the air, and the sound of my rifle was less noticeable than the buzzing of a fly.
Bang, Bang──!
The loaded magazine contained armor-piercing rounds.
I squeezed the trigger three times.
Armor-piercing rounds had the highest penetration power among all the ammunition I had.
Even a Grade-2 monster species in its weakened state could have its hide completely pierced, especially with the blade bullet effect increasing the penetration force.
[Kieeeeeeeek────!]
All three armor-piercing rounds struck the same spot relentlessly, and on the third hit, they pierced through the Mutated Quetzalcoatl's heart.
With the weakened defense exploited by the [Blade Rounds] effect, its resilience crumbled.
[Gyaaak!]
The Mutated Quetzalcoatl, which had been soaring through the air, plummeted helplessly to the ground.
Despite having endured the JD-074 thermobaric explosion, it couldn't continue flying with its heart destroyed.
[Grade-2 Monster Species, Mutated Quetzalcoatl, has been slain.]
[Damage dealt to Grade-2 Monster Species, Mutated Quetzalcoatl, has increased by 0.05%.]
As soon as the Grade-2 monster fell, it seemed the fear effect took hold, as the nearby beasts and monsters displayed chaotic movements.
The soldiers on the Red Line front didn't seem to notice, too focused on their own engagements to pick up on such details, but I could clearly see it.
'Now then...'
I switched the Ark-15 anti-materiel sniper rifle to automatic rifle mode and replaced the magazine.
This time, it was loaded with A-985 explosive rounds.
Without hesitation, I pulled the trigger.
Bang!
Boom!
Kwakakang!
It was a shame I didn't have heavier weaponry, but the firepower of the A-985 explosive rounds more than made up for it.
Even so, something still bothered me.
'If I keep spamming A-985 explosive rounds like this, people might start getting suspicious.'
Of course, amidst this chaotic noise, few would care how many bullets I fired.
But still, there was always a chance that someone might notice.
And that wasn't the only reason.
'After all, I'm still under suspicion from Ark.'
That's why I decided to change my approach to gain Ark's trust.
Now that I was here, stopping the fourth wave was practically guaranteed.
What mattered more wasn't just clearing the wave, but how to do so with the least possible damage.
'I'll start by supporting the weaker areas.'
I scanned the Red Line Gate front.