Chapter 1

"In the great hall underground in the Demon King's Castle, I muttered those words.

At the center of the room, a giant crystal was placed, and dozens of men and women stood around it.

Among them were those with dragon scales and fangs, possessing appearances far removed from humans,

...but of course, they are demons.

Compared to myself, who looks no different from a human except for the small horns on my head, everyone else seemed stern.

...despite being the same age as me.

The over a hundred people here are the demons who have turned twenty this year.

Although demons are long-lived, they have few children, but this year is said to be relatively high in numbers.

...In the past, it was common for only a handful to gather at the Demon King's Castle.

When demons turn twenty, they go to the Demon King's Castle and create a dungeon. This is a traditional custom.

There, they will live in the dungeon they create while learning how to use their demonic powers and how to expand the dungeon at the school attached to the Demon King's Castle.

In other words, the Demon King's Castle also serves as an educational institution.

"Then, we will begin the class selection test and the creation of dungeons!"

Right now, that education was about to begin. The professor, standing next to the giant crystal at the center of the room, started calling out the names of this year's new students from the list in his hand.

"Vampire demon, Sophia Grave! Come forward."

"Ah, that's me."

The first to be called was a girl with long, slender ears and black wings. Although not particularly tall, she had a revealing outfit and a seductive white skin, giving her the appearance of a sultry vampire.

"Sophia, you are... indeed, a noble from the prestigious vampire family, the Graves. I have high expectations for you."

"Hehe, thank you. ...So, I just need to touch this crystal, right?"

"Exactly. By touching this crystal—the Mother Core—your dungeon will be created and registered within it, depending on your abilities."

"Um, during my time at the school, I will live in the registered dungeon, right?"

"Yes. However, it will also be a lifelong home that you can use even after leaving the school. So, imagine your castle clearly."

As the professor spoke, the vampire touched the crystal. Instantly, the crystal glowed a faint red.

Then, the red light began to project a map of the dungeon on the surface of the crystal.

"Wow, this is amazing. To create an A+ grade dungeon with ten floors at the initial stage. The vampire demons are an excellent race, but you are exceptional."

"I received appropriate training at home."

"Hmm, then you will go to the advanced class."

The room buzzed with murmurs at the professor's words.

"To go straight to the advanced class... this year is intense."

"Yeah, not only is she from a noble family, but to create an A-grade dungeon on the first try, it's no joke..."

Amid the murmurs, I was looking at the dungeon map floating in the crystal.

Creating a dungeon is a kind of trial of strength.

If you are strong, you can create a large and deep dungeon; if you are weak, a small and narrow one.

Therefore, powerful nobles and royal demons create A or A+ grade dungeons, while ordinary demons create D or C grade ones.

Based on the abilities shown by the results, students are divided into the advanced class and the regular class, and the content they learn also differs.

...But, since it's just a place to live, a small one is fine.

I think a space with four rooms, each about four and a half tatami mats, would be sufficient.

A larger one would make moving around difficult.

I plan to live a peaceful and relaxed life in a house-sized space while learning how to use my powers in the regular class at the school.

And then, I can return to my hometown and take over the family business as a pharmacist, or something like that.

"Next. Demon human, Chrono Alcon."

My name was called second, so I stepped forward.

The professor looked at my face and tilted his head slightly.

"Chrono, you are... a demon human, right? You seem to lack typical demonic features... Are you a half-breed or something?"

"No, I'm just a regular demon human."

I was born and raised in a simple rural area.

"I see... I apologize for the impertinent question."

"No, I'm used to it. Demon humans don't have any distinct characteristics like other races."

The only difference from humans is the horns on my head. It's understandable to be mistaken.

"I appreciate your understanding. —Now, I apologize for taking your time. Imagine your castle lightly and touch this Mother Core."

When asked about a castle, I think four rooms, each about four and a half tatami mats, would be enough and satisfying.

If that's considered luxurious, a slightly larger single room would also be fine.

...Well, as long as I can live comfortably, anything will do.

I'm not that strong, so I expect to create something average. I'm looking forward to the relaxed life I can have in the regular class.

With such a light-hearted attitude, I touched the crystal. Instantly,

"!"

The crystal turned a deep black.

"Huh?"

Then, the darkened crystal emitted a black light, drawing a massive map.

It covered the entire crystal.

However, the map didn't just cover the crystal.

"Whoa!? What is this black light!?"

The black light spread throughout the room, projecting the entire map of the dungeon.

"Is this... a cataclysm!? It's scary...!!"

The people around the crystal were shocked by the sudden event.

"What is... what is happening!?"

Even the teacher in front of me was flustered, wiping cold sweat and looking around the crystal.

Then, after a few seconds, the professor, with a pale face, muttered.

"Four hundred... floors...? What is this vastness? It's not just A or S grade. This is a legendary Demon King class dungeon...!?"

"Huh?"

I couldn't understand what the professor was saying. What does he mean by Demon King class?

"What kind of power do you have...! And what did you imagine!"

"Well, I'm just an ordinary demon from a rural area."

And what I imagined was just a normal home that could be a dungeon. I don't understand what's happening myself,

"Anyway, Chrono, come here! And let's go to the Demon King!"

"Um...?"

My plan to live a calm and comfortable life in a four-room house seems to have gone awry.

The next chapter will be updated around 1 PM."