“Even if we go outside, wouldn't it be better if we learn photosynthesis?”

[Setting aside whether we can learn plant abilities, do you really know what lies at the end of this labyrinth?]

“I'm just trying to be hopeful.”

As was my routine, I dispatched trees from the back mountain and evaluated the situation. The seemingly formidable creatures of the fifth floor couldn't withstand the collective assault and were devoured one after another. They were solitary beasts, incapable of forming groups, and thus had no other option. The ants of the fourth floor, who attacked in swarms, appeared to be stronger.

[The plentiful prey on the fifth floor provided an abundance of energy, significantly aiding our species' evolution. This will be a moment etched in history, the moment we ascend to a higher form of existence.]

“...We need to grow bigger. We can't live as ants forever.”

The legion that had eaten the relatively advanced animals of the fifth floor began to grow in size. Until now, we lacked data on large animals, but not anymore. As the accumulated data increases, the modifications and optimizations that we couldn't properly utilize before will occur more quickly and diversely.

[Based on the toad, soldiers with shells and corrected body shapes are now harvesting and crushing mushrooms.]

The newly created soldiers were large. They crushed the large mushrooms with their strong jaws. The crushed mushrooms were broken down by the roots of the nest and the smaller decomposers produced, and converted into nourishment. The nourishment in those thick, large mushrooms seemed to be several times more than the trees I was providing.

[The new soldiers have also taken control of the air, hunting those who lived on the walls and ceiling.]

We had been dividing and distinguishing the types of soldiers even when we were at the cellular level. Although the toad's body was used as a base, the only similarity was that it was a four-legged vertebrate. Rather, the new legion soldier, which could be called a ‘’composite', was equipped with everything from a thin body, bat wings, shells, jaws, and a poisonous tail. Flapping its wings, it left for reconnaissance on the next floor. I also left my spot. It was time to eat.

“What kind of game are you playing so much?”

“Huh?”

I was surprised by the sudden question while I was eating quietly. My younger sister, Kang Do Yeon, was looking at me with a frown, having stopped eating. I glanced at the cell phone I had casually placed on the table.

“It's nothing.”

“You've been complaining about the upcoming exams, but you're just playing games on your phone.”

“Why are you suddenly interested?”

I chuckled. She usually didn't care about what I was doing.

“Never mind. Anyway, the exams will be over next week.”

“Right.”

While talking, I realized why she brought this up. I couldn't have forgotten in the first place.

“I remember dad's anniversary, so don't worry.”

“...Okay.”

She glanced at me and started eating quietly again. The atmosphere became strange for a moment, but it quickly dissipated. I finished my meal and got up from my seat first.

“It's a game, huh... When does the tutorial end? Why isn't my account level increasing?”[The tutorial will be cleared when you reach the 10th floor, that is, when you pass the 9th floor.]

“Doing as you please.”

Now, the 6th floor is being plundered by us. With this rate of growth, it doesn't seem too difficult.

[Look. This is evidence of the legion evolving into a higher life form.]

One screen was shown on the screen. This place is the lowest level, our origin. Here, where our nest has completely covered, a disgusting flesh wall was wriggling.

“Hmm...”

[Do you think it's disgusting? That pulsating flesh wall mimics the internal reproductive organs of a higher life form.]

“Why on earth?”

[It's for efficiency.]

I frowned, scrutinizing the flesh wall. As per the explanation, this wall was a magnified version of reproductive organs, detached from the body. It was, quite literally, a nest. The entire legion was gradually specializing. Those focused on production were honing their skills, while those dedicated to thought were sharpening their intellect.

[The newly refined production system begins to operate.]

The wriggling of the flesh wall intensified, and something began to tear through the meat wall and appear. It was a large egg.

[The legion, which has introduced the concept of ‘growth' beyond simply replicating itself like a tumor, was able to dramatically increase the energy efficiency involved in raising troops.]

The eggs produced from the flesh wall grew faster than before, breaking the eggs and hatching. Such nests are filling the entire occupied floors, and such eggs are pouring out by the hundreds and thousands.

[And look. An organ that can be called a proper brain tissue is also being created. It even has a concept of investment. It already recognizes the need for advanced and specialized nerve tissue. This will be recorded in history. We don't know when, but the fully developed brain of our species will surely have a self.]

Not only the production organs were located at the lowest level. The deepest and safest place. There was a brain connected to the legion. It's just a pilot organization that doesn't help much yet. But as more data is accumulated, that brain will definitely grow bigger.

*

“What is this?”

[These are new types of enemies.]

The moment I woke up from sleep, I found my phone in a daze. There was no need to look at the clock, lust looking at the color outside the window, it was still early dawn.

“What is it?”

I rubbed my eyes and examined the screen. On the seventh floor, our newly produced large reconnaissance soldiers were annihilated in a place that was supposed to be nothing special when we first scouted.

[It's the same as before. Things that we couldn't scout with small entities reacted this time.]

“What on earth...”

A new reconnaissance soldier was dispatched. This time it was a small entity based on a bee. That entity found the enemies that it couldn't detect last time.

[They are the double-winged bats we hunted on the 5th and 6th floors.]“...Why are there so many?”

The ceiling of the hive was shown. And those densely packed there were definitely bats. They looked to be at least several hundred. Knowing that these alien bats are the size of a young child, I got goosebumps.

[They hardly qualify as a ‘legion'. They merely coexist, each hunting independently on different floors.]

“Still, if that multitude of bats were to attack us, we wouldn't stand a chance, lust consider the physical disparity.”

I voiced my thoughts with a hollow chuckle. I was gradually getting the hang of it, but the conclusion I reached was grim. The legion's power was insufficient for a direct confrontation with the bat swarm.

I chuckled to myself, muttering under my breath. As I was slowly getting the hang of it, the conclusion I had come to was impossible. The strength of the legion was insufficient to engage in a head-on battle with that bat colony. We could produce superior combat soldiers of a similar weight class, but then we wouldn't be able to match their numbers.

[That's not what we're thinking about.]

“What?”

[Didn't we tell you? The legion never stops. Right now, we're actually quite pleased. If we can use those numerous pieces of meat as nourishment, we can create a large force like those bats.]

“How do you plan to fight?”

[...Trust us.]

The legion had already begun to move. I wasn't sure what they were up to, but at least it didn't seem like they were thinking of a head-on fight. They were even willing to kill off their existing soldiers and convert them into nourishment.

“I'm really curious about this.”

For now, I got dressed. I was considering cramming for today's test.

[The legion has devised the first tactic.]

Soon after, the legion began to release the accumulated energy again. I carefully observed the nest. Something started to crawl out of the tiny eggs.

[The first tactic chosen by the legion was a cunning one. But we're not sure if it will work.]

There were small creatures crawling on the walls. They had only one weapon: a poisonous sting. That sting contained the most potent poison the legion had created, the Acidic Poison. They had chosen this covert battle as soon as they realized a frontal confrontation would be difficult.

[The Acidic Poison was indeed effective against bats. But the execution rate wasn't very good. A few careless bats fell to the ground, but the bats were originally creatures that ate these small creatures.]

The exchange rate was not good. The bats easily detected the approach and devoured the poison bugs. The Acidic Poison was meaningless unless injected into the bloodstream. Moreover, the creatures in this cave, including the bats, were generally resistant to the poison due to the mushrooms they ate.

“So what now? It seems like we've tried everything we have.”

[The legion has chosen the second tactic.]

As I prepared to leave, I watched the progress. There was no additional movement. However, the meat walls that completely covered the second floor suddenly hardened.

“What is this...”

[The legion temporarily put the two-floor nest into hibernation as explosive energy was needed.]

What on earth for? I turned the screen to the entrance of the sixth floor. I realized their intention there and let out a hollow laugh.

[Imitating the tactics of the White Cave Ants that resisted from the fortress, the legion decided to wage a siege.]

“That doesn't seem like the siege I know of.”

Since when did a siege mean hitting with a fortress?