Why is my Isekai in the Slice of Life anime was become a Horror Story?

Interlude 1-20: The Dream and the Moment Before the Mission Begins

Drip—

Cold droplets fell on his shoulders, carrying a distinct chill.

Once again, he dreamed the same dream.

A dream of himself reaching forward.

A dream of himself crawling through a deep, bottomless cave, surrounded by utter darkness.

He couldn't find the right words to describe the sensation.

If he had to compare, perhaps he would think of an experience from his childhood.

As a child, before falling asleep at night, he would sometimes deliberately roll over to wrap himself tightly in his blanket.

It felt like being bound tightly in that way.

But the difference was, the surrounding rocks were hard and cold.

Every moment, he could distinctly feel his skin rubbing against the rocks, hear the sound of his body inching forward through the cave, creating friction.

It sounded as though the rocks themselves were screaming.

Drip—

The source of the dripping water was indiscernible.

Only the cold sensation spreading throughout the cave, slowly intensifying.

Huff… huff…

He could hear his own breath, growing heavier.

He continued struggling forward, crawling a little further.

Time seemed to stretch endlessly in this moment.

He didn't know how long he had been moving through the darkness.

He didn't know what awaited him ahead or when he would reach the end.

Huff… huff…

But he could hear breathing.

The sound came from behind him.

From deep within this narrow cave, where even turning back was impossible, where all he could do was continue crawling forward, came that breathing.

Drip—

Amid the sound of water dripping once more, Takakai heard something crawling behind him.

The sound of flesh rubbing against stone.

The sound drew closer, inch by inch, coming closer to him.

Right behind him.

He struggled to move his arms, gripping the rocky walls, continuing to inch forward just a little more.

He couldn't even pull his arms back. He had to keep them stretched forward just to barely crawl through the narrow confines of this cave.

He couldn't lift his head.

Even tilting it to the side, his ear would brush against the cave's ceiling.

With the constant scraping, his ears were torn, to the point where the pain itself seemed to fade.

He couldn't see anything.

Nothing but pitch-blackness, with no light source in the cave. All he could sense was the smell of dirt.

Huff…

The breathing behind him seemed to be drawing closer and closer.

But he still couldn't see anything.

All he could do was inch forward slowly, continuing to move through the suffocatingly narrow cave.

Drip—

He heard the sound of water dripping again.

Takakai gradually stopped moving forward.

He could no longer hear the breathing or the crawling sounds behind him.

In this silent darkness, it seemed once again that he was alone, or perhaps, he had always been alone to begin with.

Huff…

Just as that thought arose, he heard new breathing.

This time, not from behind him, but from ahead.

Along with the sound of something crawling, the noise slowly approached, the breathing coming closer with each moment.

There was no way to retreat.

The narrow cave twisted, and while advancing, he could hold onto the walls to pull himself forward. But going backward was nearly impossible—he couldn't see the structure of the cave behind him, nor could he find a foothold.

Huff…

Takakai struggled, trying to retreat, but he could only move back a tiny bit, inching at an excruciatingly slow pace.

Huff…

And the breathing from ahead grew closer, closer still, until he could feel it brushing against his cheek.

Huff…

He truly felt it.

There was someone—or something—directly in front of him, crawling face-to-face.

He couldn't see the person's face or their figure.

But this cold breath against his face clearly told Takakai about them, about the presence right before him.

He reached out.

Slowly, extending his hand forward, inch by inch.

Huff…

A cold gust brushed across Takakai's skin.

But his fingers reached nothing. Only air. They touched the cold, rocky walls on either side.

There was no one else.

He was alone.

The one struggling in this suffocatingly narrow cave—was only himself.

...

Drip—

The sound of dripping water echoed again, and Takakai slowly opened his eyes.

The sunlight outside the window remained dazzlingly bright.

People strolled leisurely along the street, chatting about their plans for the day, living lives no different from yesterday.

Takakai sat up on the bed and touched his ear. It was intact, without a single scratch. Then, he looked at the calendar hanging on the wall, where he had been crossing off each day, his gaze finally settling on the few remaining dates.

He stretched out his hand and counted. Only three days left.

This meant the next mission would begin in three days.

Since that deal, everything had been calm.

Shijo Maki had invited him to go shopping a few times, but perhaps because of being taken advantage of last time, she had grown far more cautious. At most, they held hands, but anything beyond that, like kissing, was almost out of the question.

Kaguya occasionally went out and even organized a few tea gatherings for the three of them. However, her gaze toward him seemed to have changed, tinged with a bit of wariness.

Takakai didn't understand the psychology of girls, but one thing was clear—this month was passing without much progress.

One notable event was Shijo Maki arranging for Takakai and Kaguya to sneak into a private shooting range reserved for the upper class. She even invited professional trainers to teach them how to use and maintain firearms.

Taking into account the environment of the upcoming mission, Maki had procured two standard pistols modified to adapt better to humid and sandy conditions in the caves. But how effective they would be in practice could only be determined during actual use.

No, it would be best never to find out. Guns were tools for dealing with other players, and if they had to resort to such weapons, it would mean competition and conflict between participants in the mission. After his experiences with Old Guo and the female mole, Takakai despised those who caused infighting among the player community.

There were several unread messages on his phone.

One was from Kaguya, detailing the gathering point for three days later.

The other was from Maki, checking in on him and adding a playful line: "Lazy bum, stop sleeping and get up already!" when she realized he hadn't replied.

Takakai got up, picked up the black pen on the bedside table, crossed off another day on the calendar, and turned to leave to wash his face.

All necessary equipment had already been prepared.

Exploration clothing, Cut-resistant gloves, Helmet, Knee guards, Hiking boots, Headlamp, Disguise outfits for blending in as tourists

To handle unexpected situations, the three of them had devised some contingency plans.

Amid the sound of running water, Takakai finished washing his face.

Picking up a towel, he gently wiped the droplets from his face.

Drip—

The dripping sound from the faucet caused Takakai to freeze momentarily.

"Have I been getting too sensitive lately?"

He recalled the dream, the third time it had repeated.

The scene of himself crawling through a narrow cave, hearing something following behind, only to discover in the end that he had been alone the entire time.

A dream filled with pressure, gloom, and eeriness.

Perhaps it was an omen.

But giving up the ticket in his possession because of such an omen was something Takakai couldn't do.

No matter what, it was still a Dusk-level ticket, a pass into a dungeon where he had gathered a lot of information in advance.

To abandon it would mean preparing to face separation from Kaguya and Shijo Maki, stepping into an entirely unknown world—a choice that was clearly unwise.

"..."

Takakai extended his hand, using his finger to block the stream of water from the faucet. He stood silently in front of the sink. Only after a few minutes did he turn and leave.

Today was just another uneventful day.

One more check of the luggage.

Waiting for time to inch forward, waiting for tomorrow to come.

Takakai was beginning to understand what the word "torment" meant for players.

No matter what he thought, that fateful day would still arrive.

Three days, two days, one day...

Until the day the game began.

.....

"Ready?"

When he pushed open the door to the small room Shijo Maki and Kaguya had reserved, the two girls were already prepared, their equipment neatly packed beside them.

"At this point, saying 'not ready' is already too late, isn't it?"

Takakai slung his equipment backpack over his shoulder and sat down next to Shijo Maki.

The dungeon ticket was securely in their hands.

No one said anything further.

Only the sound of their breathing and the oppressive atmosphere lingered in the room.

"It'll be fine," Shijo Maki finally broke the silence, reassuring the group.

"If we get separated inside, we need to regroup as soon as possible," Kaguya added. Yet, the icy composure that usually adorned her face seemed to crack the moment she spoke. Even someone as strong-willed as Kaguya couldn't completely maintain her calm as they prepared to enter a new death game.

"Yeah."

Takakai didn't know what to say, but remaining silent felt inappropriate for the moment. He simply nodded slightly in agreement, a minimal effort to show cooperation.

And so they waited for that moment, feeling the countdown to a number only they could sense gradually tick toward zero.

Boom—

The ticket in each of their hands ignited, burning without the need for wind.

A strange voice echoed in their minds.

[Welcome to the 'Sacrifice Game.']

[The game level you are about to participate in: Dusk.]

[We hope you can witness the end of everything amidst true fear.]

As the voice faded, all senses plunged into darkness.

The first sound Takakai heard after that was the crisp echo of a droplet hitting the ground.

Drip—