.

“…Mr. Jang Sawoon. Would it be possible to kill them all by shooting underwater?”

Although he asked with a glimmer of hope, he received a pessimistic answer.

“Bullets can only travel up to 3m underwater. We could create a specialized underwater firearm, but it would only be slightly better than a regular rifle.”

“So, it won’t work.”

“Correct. To kill that monster, it seems we’d have to go underwater and engage in close-range gunfire.”

In that case, on to the next option.

“Mr. An Jiwoo, what about attacking with water elementals?”

“I’ll give it a try. Undine!”

An Jiwoo immediately summoned Undine to attack the mutant zombies.

However…

The mutant zombies were swimming deep, dozens of meters underwater, and the blades of water shot by Undine lost their force before reaching them.

“…It won’t work. It seems we’ll need to get closer to attack.”

“So the conclusion is, we have to go underwater to fight.”

“That’s what I’m saying…”

An Jiwoo adjusted her golden-framed glasses and spoke.

“If I use Undine’s blessing on you all, you will be able to breathe and talk freely underwater for a certain amount of time.”

“Wow!”

“That makes the situation much better!”

Everyone’s faces brightened, but An Jiwoo continued with a neutral expression.

“However, doing so will consume a lot of my mana, making it difficult for me to fight properly. You’ll have to defeat the monster and destroy the nest yourselves.”

The meaning was that An Jiwoo, ranked 21st, would be excluded from the fight, but the expressions on people’s faces were not that grave.

With so many high-ranked individuals gathered, the absence of one wouldn’t significantly weaken the team.

The attention then shifted to a few individuals—me, ranked 1st; Ryu Sein, ranked 3rd; and Jang Sawoon, ranked 9th.

Being the most powerful individuals among us, it was hoped we could respond to An Jiwoo’s concerns.

Before I could say anything, Ryu Sein spoke first.

“There’s no problem. As long as we can breathe underwater, I can destroy the nest even under the worst conditions.”

“Sein, you don’t mean…”

“It’s fine, Dad. I’ve had no shortage of mana lately.”

Ryu Sein responded with overflowing confidence.

Ryu Jinyong seemed a bit concerned, but Ryu Sein lightly smiled as if it was a needless worry.

“Alright. Let’s get started right away. Undine!”

An Jiwoo immediately bestowed Undine’s blessing upon us.

.

Splash-!

We all dived into the water.

“Wow…!”

It was an amazing feeling. The fact that we could speak and breathe freely underwater was incredible.

The water was neither cold nor too warm, a pleasantly tepid temperature.

From the depths, a subtle light emanated, creating a mysterious atmosphere.

Bae Seongjung pointed downwards and spoke.

“What is that light?”

The answer came from Kang Minki, who was a power plant worker.

“It’s Cherenkov radiation.”

“…?”

Bae Seongjun looked at him with an expression that seemed to say, ‘What the heck are you talking about?’

Kang Minki elaborated further.

“It’s the phenomenon that occurs when high-energy particles emitted from radioactive material move faster than the phase velocity of light.”

“Shit, radioactive material? So, is this entire body of water a lump of radioactivity or what?”

“No, as I mentioned earlier, water is one of the best materials for shielding against radiation. The water is perfectly fine as long as we don’t get too close to the nuclear fuel rods or the uranium inside doesn’t leak. It only contains a small amount of boron.”

Bae Seongjun closed his mouth, his face wrinkled in concern.

We swam deeper, and mermaid monsters and mutated zombies were watching us, waiting on the water floor.

“I have a bad feeling about this. It seems like those creatures are luring us deeper.”

Jang Sawoon said this with some worry.

I responded to his comment.

“Even if that’s the case, we have no choice but to go deeper to destroy the nest.”

“…True.”

In the tense atmosphere, Ryu Sein spoke confidently.

“Don’t worry. I will destroy the nest.”

At this point, I was really curious.

What was Ryu Sein’s secret weapon that gave her such confidence?

We wouldn’t have to wait long to find out.

As we got closer to the bottom, fifty mutated zombies with fins emerged to greet us.

“Kyakyakyak!”

“Kyarrlrlrl!”

“Kyark, Kyarrk!”

The mutated zombies made eerie noises as they charged at us.

“Awooooooooo—”

With a howl, Bae Seongjun transformed into a werewolf, marking the beginning of the battle.

“Thw-thw-thw-thw-thwoom—!”

Jang Sawoon conjured up a strangely shaped gun and began firing at the enemies. It seemed to be the underwater firearm he mentioned earlier. However, its bullets weren’t as fast as those from a rifle shot above water, allowing many of the enemies to dodge.

The mutated zombies moved at terrifying speeds even underwater, attacking us aggressively.

I drew the short sword strapped to my waist and sliced through the waist of an approaching mutated zombie.

“Kyarrlrlrl!”

Thanks to [Celestial Blessing], my blade cut through like butter, severing the mutated zombie’s spine.

And then…

“Master, watch out below!”

Serena’s urgent cry rang out.

I tensed my body quickly and looked down.

Between the nuclear fuel rods, the nest was rooted. Next to it was a mermaid monster, winding up, its right hand gripping a nuclear fuel rod.

It was clearly preparing to throw a spear.

The same attack that had almost killed Hyun Seohee when we were above water!

“Dodge it!”

As I shouted, the nuclear fuel rod ripped through the water like a harpoon.

Its target was not me but Ryu Jinyong, who was fighting a mutated zombie.

Unaware of the incoming attack in the heat of the moment, Ryu Sein cut in front of him.

“Father!”

Cling-!

With her sword, Ryu Sein slashed, successfully severing the nuclear fuel rod.

Black substance spewed from the severed nuclear fuel rod.

“No! It’s uranium!”

Kang Minki quickly extended his hand to control the water flow.

“We shouldn’t destroy the nuclear fuel rods! Even in water, we can’t completely block the close-range radiation exposure!”

He sent the severed rod far away.

Still, it seemed like we couldn’t fully prevent the radiation exposure; I could already taste the metallic tang in my mouth.

“Grrrr… this is a crappy situation.”

As Bae Seongjun said, the situation was indeed not good.

There were more than 40 mutated zombies remaining.

We hadn’t even been able to kill 10 despite our numbers.

The underwater environment was more disadvantageous than we’d thought, and the mutated zombies’ movements were too agile.

Furthermore, the most serious problem was…

“Heh heh heh, heh heh—!”

That mermaid monster was preparing another spear while letting out a heavy, eerie chuckle.

The need to defend against these nuclear fuel rod attacks while also dealing with mutated zombies was splitting our focus.

There was no room for slack now.

“Serena—”

Just as I was about to command my white knight, Ryu Sein charged forward, shouting,

“I’ll destroy the nest! Just hold off the mutated zombies for a while!”

“—Serena, protect Ryu Sein.”

“Yes, Master!”

I decided to trust her for now.

We were each reducing the number of the mutated zombies. Ryu Sein appeared to be focusing intently, pointing her sword forward with her eyes closed.

“The next attack is coming!”

Following Jang Sawoon’s warning, the mermaid monster shot another nuclear fuel rod.

This time, the target was Ryu Sein. Serena stepped forward and kicked the rod away.

“Cling-!”

Hyun Seohee, who had been wielding a folding fan and shooting blades of water, exclaimed with admiration,

“Amazing, Serena!”

Ryu Sein continued to focus without even opening her eyes, trusting Serena.

Gradually, her sword started to change.

A faint red light emerged from the blade, growing more intense and engulfing the sword in an aura that kept expanding.

Observing this, Ryu Jinyong shouted,

“Sein, don’t overdo it! If you lose control here, we’re in big trouble!”

Whether she heard the warning or not, Ryu Sein’s face paled, but she kept concentrating.

The red aura grew larger, eventually expanding to at least 1.5 times the size of the sword.

Seeing this, even the mermaid monster seemed to sense that the situation was getting serious and stepped forward to protect the nest.

Finally, Ryu Sein opened her eyes.

Gazing at the mermaid monster blocking the nest, she smiled faintly and swung her sword.

“If you can stop it, try!”

Despite the urgent fight against the mutated zombies, everyone’s attention turned to Ryu Sein.

A crescent-shaped burst of red aura flew from her swinging sword.

At that moment.

The mermaid monster mockingly twisted its face and turned around.

For the first time, its back was visible, and on it was an evidently thick black turtle shell.

‘Could it be…?’

The crescent-shaped aura collided with the turtle shell.

Kwaaaaaaang—!

As if a massive explosion had occurred, a powerful shockwave hit us all.

“Grrr!”

“Aaaah!”

“Grr…!”

With a dazzling red flash that almost blinded me, I squinted at the mermaid monster.

The aura Ryu Sein had fired definitely boasted immense power.

It not only penetrated the monster’s shell but almost tore the creature in two.

However, the end result was a failure.

Her objective had been to pierce through the mermaid monster and destroy the nest, but she hadn’t even managed to kill the monster.

“What the heck, it actually got blocked?”

Baek Seongjun mumbled as if mocking Ryu Sein.

She groaned, almost whispering,

“This can’t be… how could the Qi be…!”

Feeling that Ryu Sein was considerably shocked, I offered her some comforting words,

“It’s alright. You inflicted significant damage.”

“……”

However, Ryu Sein did not look alright at all.

For starters, her complexion was extremely pale.

Tututututututu—!

Regardless, we continued the battle, effectively reducing the number of mutated zombies.

Now, only about ten remained.

If we finished off these and then dealt with the half-dead mermaid monster, it would be over.

But then…

“Heh heh, heh heh heh—!”

The mermaid monster, lying half-cut at the bottom of the water tank, began to indiscriminately tear apart and devour the nearby nuclear fuel rods.

The monster started voraciously gulping down the uranium inside the nuclear fuel rods as if they were chocolate balls.

“What the—!?”

Kang Minki was momentarily flustered by this sudden development. The mermaid monster’s bleeding stopped, and new flesh began to grow over its wounds.

Simultaneously, due to the released uranium in the water, the mysterious light known as Cherenkov radiation became even more intense.

Kang Minki muttered in horrified disbelief,

“This can’t be… The bottom is now a hell of radiation! To destroy the nest, we either need to attack from a distance or approach it prepared to die from radiation exposure!”

“……”

Despair filled the faces of those who heard him.

Baek Seongjun spoke for everyone,

“Grrr… Attack from a distance? Even that Qi attack or whatever got blocked, and the monster has recovered?”

“……”

For some reason, the mermaid monster regenerated its wounds as it ate the uranium.

Its dark shell was almost entirely restored now.

“I could… I could use Qi again—”

“No!”

Ryu Jinyong shouted, interrupting Ryu Sein’s weak voice.

“If you use Qi again, you’ll undoubtedly face dire consequences!”

“But—”

“Serena.”

I cut off Ryu Sein and called for Serena.

“Yes, Master.”

She had already done her best.

Although we initially wanted to stand by and see if the situation could be contained by the strength of the other Rankers, it seemed impractical.

So, it was our turn now.

“Arm yourself with White Knight armor.”

“Understood.”

A white aura enveloped Serena, and she materialized armor that covered her entire body, along with a Zweihänder as large as me.

Her figure, visible under the water, had a mysterious atmosphere, further enhanced by the Cherenkov radiation reflected in her armor.

“Let’s go down. We will kill that mermaid monster and destroy the nest.”

There was no need to fear radiation exposure as long as it didn’t kill us instantly; [Grace of Light] would heal us.

Serena and Ciel responded by my side,

““Yes, Master!””

While everyone stared in puzzled astonishment, we proceeded toward the mermaid monster.