A bloated, gigantic zombie stands in my way.

Its height is enough to touch the ceiling just by standing, and its girth fills up half the hallway, completely blocking the path.

However, one of its arms is torn off, and the other is hanging on by a thread of skin.

Furthermore, its right thigh is also gouged out, forcing it to its knees, unable to walk properly.

"Spread... Dagger!"

From about 2 meters away, I unleash the skill that finally finished its cooldown.

The duplicated daggers fly and pierce the head of the "Ghoul," the evolved form of the Zombie Leader.

And the moment the blades split inside, its head bursts with a pop!, scattering blood.

But right after that, a black shadow flies from behind the fallen mass of meat.

It was something like a human head—connected by a long, extended spine.

The "main body" is the evolved form of a Zombie Wolf... some unknown creature.

In short, it's an individual that underwent a different evolution from the Spider, an exceptionally creepy monster whose head multiplied and attacked by launching them.

I lean back, evade the biting head, and slash the connecting spine with Dreamer.

However, no matter how much I cut, a new face sprouts from the tip shortly after.

Is it respecting some national hero or something?

Until just now, it was incredibly annoying, launching heads from behind the Ghoul.

But alone, it can be dodged, approached, and chopped to pieces!

"Enough already! Just dieeee!"

Since I used up my skills to defeat the Ghoul, I just stabbed it.

It's annoying that its torso hasn't changed much in appearance, yet it's harder than a Zombie Wolf.

But since I've gotten stronger too, the thrust blade successfully reached its heart, allowing me to kill the opponent.

[Monster 'Cerberus' killed. Congratulations, you have leveled up to 22!]

What a cool name it has.

"Many-Stretching-Necks-Man" or something would be fine, since it's gross.

In any case, with this I've defeated all the monsters blocking the way.

I want to look for Yumemi chan but there's something I need to do first.

"It's cold and heavy and it's the worst... just being painful is better..."

I was bitten a few times by the Cerberus earlier.

Since it's undoubtedly a fellow zombie, when I lifted the uniform over my bitten abdomen, I could see a blue bruise spreading.

On the status screen, [Status Ailment: Zombification] is shown.

But I'm a little relieved.

Since this is treated as a status ailment, it means a means to cure it is also prepared.

Well, since it uses precious skill points, it couldn't be helped that learning it was postponed.

First, I'll raise the level of Healing—

[Remaining Skill P: 6]

[Learned Skills]

Healing Lv. 3

Ugh, the MP cost increased from 3 to 5.

So magic consumes more as you raise its level.

Though its power probably increases enough to be a net positive.

And with this, I can learn the higher tier skill of Healing.

[Remaining Skill P: 5]

[Cure Lv. 1 MP Cost: 5]

[Recovers status ailments]

The one that healer characters often learn.

But the cost at Lv. 1 was higher than I thought.

Since I used MP in the battle earlier, the remaining 5 was cutting it close.

Holding my hand over my body and chanting "Cure," the emitted light erases the blue bruise wriggling inside my body.

My body temperature returns, and the heaviness disappears.

A sigh of relief.

Exhaling—I immediately look forward.

I'm sure the person who looked like Yumemi chan went into the classroom on the side.

To be honest, I don't want to open it.

This isn't a normal classroom, but a classroom "that shouldn't exist," created by the expansion of the school building.

The plate installed above is spelled with unreadable characters.

In the red hallway, zombies swarmed out from these kinds of doors, so I can't imagine it connects to a decent place.

But I can't let that girl get away.

I put my hand on the closed door, take a breath "phew," and open it in one go.

"What is this..."

I muttered involuntarily.

Before my eyes—a vast desert spread out.

A desert that truly seemed to continue forever, with a dry wind caressing my cheek.

But there is no sun in the sky, and it was a dull, murky green.

It's not covered by clouds, but the sky itself is that color.

And the sand covering the ground also seemed to have a darker color than what you see on a beach.

I crouched down and picked up the sand.

As expected, even when brought towards the lit hallway, the sand has a color like a corpse.

There's no sign of life in the desert, just an endless expanse of dead land.

"Dead... no, rotting"

I intuitively thought so.

Furthermore, straining my eyes at the horizon visible in the distance, I see something black wriggling and swarming.

There is nothing beyond the black object.

Just a jet black nothingness.

It looked as if that blackness was eating the world.

"The world is rotting away... and perishing..."

Kaigyo's Gangrene.

That incomprehensible phrase and the sight I'm currently looking at seemed to share a commonality.

But my goal isn't to observe this space.

It's to search for Yumemi chan.

Looking around, I don't see any sign of her.

Should I go into the desert and look—as I thought that and stepped forward, the other door of the same classroom opened.

From there, the blonde girl appears.

"Yumemi chan!"

I hurriedly chase after her, but she went into the next classroom again.

"Don't run away, Yumemi chan!"

I jump into the door left wide open.

What was there was a messy cityscape with countless buildings standing close together.

There is no floor beneath my feet, and if I step carelessly, I'd fall headlong dozens of meters down.

The air is so bad it makes me cough involuntarily, and I can confirm the figures of human like creatures on the ground—

"...Those people are rotting too."

Their skin is crumbling away, and they're rolling on the ground, desperately reaching out as if asking for salvation.

Many, many such people—unlike zombies, their intelligence remains, making them look as if they were afflicted by an unknown disease.

And then, I hear the sound of a door opening again.

Immediately directing my gaze there, for some reason Yumemi chan appears from a door three doors down.

"Why are you coming out from a place that far away!"

My game of tag with Yumemi chan continued for a while.

Each time, I witness various worlds beyond the doors.

A withered, gray forest.

A dead, dark red sea.

A land that forgot heaven and earth, falling endlessly.

A universe where an endless void exists without even stars.

An inorganic space floating with cubes inscribed with something resembling hieroglyphs.

A finished world where humans broken down into geometric patterns close in, trying to draw me in as a companion.

Everywhere was ruined so much that it was obvious at a glance.

It also looked like the future form of "here," where we currently are.

Why is it connected to such worlds through doors? It's a grandiose question that my understanding cannot reach even if I think about it.

So I decided not to think.

I just kept chasing Yumemi chan, chasing her, and realizing halfway that the opponent was clearly running away, I chased her even more stubbornly.

"I finally caught you!"

At last, my hand grabbed her shoulder.

At the same time, I am relieved that the possibility of a hallucination disappeared by touching her.

Yumemi chan turned towards me with a displeased face, and directed her gaze to the curved short sword—Dreamer—in my hand.

"Do you think I'm going to harm you? Haha, that means you're aware of how much you're hated."

"I cannot understand what you are saying."

Yumemi chan's voice that I finally heard.

Yes, as expected, even the voice is exactly her.

But—her way of speaking is oddly pompous.

"You have been calling me by the incomprehensible name Yumemichan for a while now, but you have the wrong person."

"Speaking in a weird tone. Stop joking around."

"I am not joking. It is inevitable that a commoner like you would be surprised by my noble manner of speaking."

"...What are you really saying?"

The more I observe, the more the gesture of putting her hand on her chest and the movement of her expressions are of a different person from Yumemi chan.

But her face is undeniably, completely Yumemi chan herself to the point that I couldn't possibly mistake it, and even her voice is the same.

"You are Yumemi chan, right. I've never heard of you having a twin, and there's no way there could be another person who looks exactly like you!"

"I may give you my name, but shouldn't you, a person of lower status, state your name first?"

"Status... sigh, fine. I am Kuragane Erika. A second-year attending Hikarinomiya Academy."

"Academy... I see, this was a place of learning."

"Look, I gave my name, so tell me. If you're not Yumemi chan, then who on earth are you?"

Someone who is not—Yumemi chan—smiled insolently and announced her own name with a proud face as if saying 'be grateful'.

"My name is Nemushia Adrak. The Queen of the great Adrasia Kingdom!"

Her needlessly resonant voice echoed through the hallway.

I'm glad there are no monsters nearby, because if it's this easy to hear, they'd probably react and come over.

"What's the matter, you should show some respect, you know?"

The self-proclaimed Nemushia tilts her head, provoking me.

It doesn't feel like she's acting.

Does this mean... she really is a different person from Yumemi chan?

"Do not remain silent. Since you made me give my name, say something."

"Um... where is this Adrasia Kingdom? Hokkaido? Honshu?"

"Hokkaido... Honshu? I know of no such place names. The Adrasia Kingdom succeeded in unifying the continent. In other words, the continent itself is the kingdom."

Nemushia stated that proudly.

If I believe her explanation, does that mean she came from a place called the Adrasia Kingdom ... no, possibly from another world?

Come to think of it, I've encountered zombies that clearly weren't Japanese many times.

"Hmm, is this place not part of the Adrasia Kingdom?"

"It's a city called Hikarinomiya City in Japan, but."

"Hikarinomiya... I know of no such place."

"Could it be that the zombies that first appeared in this school are the people of the Adrasia Kingdom?"

"Indeed, I too was attacked by monsters dressed similarly to my people."

"Was it your intention to bring them into the school? Or did it happen on its own?"

"Hah, do you think my proud kingdom would do something so vulgar? Even doubting it is a sin."

"Even if you say that, we're actually being attacked by people who turned into zombies."

"If I knew the answer to that, I wouldn't be troubled myself."

"So you are troubled."

"Did you listen to my soliloquy without permission!?"

"No, I just heard it..."

"Commoner, allow me to say this."

"Erika."

"Hmph, very well, I shall call you by your name. Let me tell you, Erika, I do not trust you people."

"That's my line, though."

"Fuhaha, you say amusing things. Try putting yourself in the shoes of someone being chased by someone holding such a dangerous blade, calling out a name that isn't theirs, Yumemichan!"

"That's... sorry."

It's true that looking at it objectively, I feel like I did something very apologetic.

But even now, I can't completely believe that Nemushia and Yumemi chan are completely different people.

Because they look way too similar.

"Hmph, you finally realized you are a suspicious person. Furthermore, since you wear those clothes, you must be affiliated with this place of learning? At that point, you are not worthy of trust."

"Distrusting the school... do you by any chance know about Kaisekyou or Giraiguu!?"

"As I thought, you are an associate."

"No, I'm hostile to them!"

"I said I cannot trust you. I have no intention of speaking further."

"Wait, I still have things I want to ask!"

Before me as I pressed her, a white orb suddenly appeared.

The next moment, it emitted an intense light, filling my vision.

By the time I could see my surroundings normally again, Nemushia was already gone.

"It didn't look like she activated a skill... hmm, is that what true magic is?"

If so, does that mean Nemushia is a real person from another world?

Even though she looks exactly like Yumemi chan.

Her scent, her touch, her body temperature, everything matches my memories.

"She shouldn't have gone far yet."

She clearly knew something about this school.

I have to catch her and get her to talk, no matter what!

There are no corners nearby, and the only place she could have fled into is a door leading to that alternate space.

I reached for the door of a nearby classroom.

Currently, even if they connect to strange spaces, we are rarely attacked from the other side.

Since it has been that way so far, unless I'm very unlucky this time—

Gii?

The moment I opened the door, my eyes met theirs.

No, they had no eyes, and their faces were completely black, but I knew their gazes were directed here.

It was a normal classroom, except it was horizontally reversed(....).

There was a teacher's desk, numerous desks lined up, and students with human shapes sitting there.

But they were human in shape only.

What was there were black monsters reminiscent of the cosmos, made of a undulated slime-like material.

Guu, Guu, Guu!

They let out distinctive cries, knocked over their chairs, and stood up vigorously.

And they rushed at full speed toward the exit of the classroom where I was.

"I'm so unlucky today!"

Since I'm basically always unlucky, being able to say "today" might be proof of progress.

Thinking such uncharacteristically positive thoughts, I sprinted away from that spot with all my might.