One thing—I might have been making a huge mistake.

Using a magic like dimensional transfer, I thought, “I might not be able to return to my original world!”

Even kids in other stories can only return to Earth after defeating the Demon King, so they end up going to fight him anyway.

Much more so for someone who used magic to travel from another world to Earth.

And if that person happens to be in the basement of the house I just bought… all the more reason.

So maybe I need to prepare a new house for this Great Mage… or something like that.

“Ugh, the house really is nice.”

Rasianne stretched and took a deep breath as she stepped out from the dimensional portal in the wall.

Like someone leaving a polluted city for the countryside, she opened her mouth wide and inhaled deeply.

A circular garden filled with brilliant flowers.

Though a curtain blocked the view beyond the wall, the inside glowed brightly despite no visible lighting.

It was—

“Ten hamburgers for dimensional travel. This is absurd.”

Only thirty minutes ago, she had been eating one of each type of burger.

She had eaten all ten now, yet her stomach showed no sign of bulging.

“It’s not ten hamburgers.”

“Then?”

“It just takes a lot of mana to open the portal. The mana itself isn’t a problem; it just passes through.”

Rasianne flung open the heavy blackout curtain.

Whoosh.

“!!”

Beyond the curtain.

The entire wall was a glass window, revealing a vast expanse of land.

It was the kind of view you’d expect from the top of a tall mountain—an immense, open landscape stretching beyond the glass.

“…Living in a house with a view like this, then landing in my own home… I can definitely tell this is another world.”

“Even the language is different.”

“Oh.”

I had noticed, but hadn’t said anything.

“Is that magic too?”

“Translation magic. A spell that makes my thoughts heard in the listener’s language.”

“……”

“Think of it as real-time AI translation. From my side, I don’t even use mana; it’s just like a program making communication possible across languages. It’s similar.”

Rasianne stood by the window and gestured for me to come closer.

I stepped to her side, standing where I could look out over the land—

“Wait.”

“…Heh heh heh.”

“This, perhaps?”

“You noticed, as expected.”

Rasianne reached forward, and a holographic image appeared on the glass.

“My home, the White Magic Tower, floats in the sky.”

“……”

“It’s placed so others can’t just enter. People of this world call it the ‘Sky Castle.’”

Rasianne traced the wall, revealing a massive floating island in the image.

At the top was a white, magnificent magical castle.

Below, land stretched down like horns supporting the structure.

“Is this possible because you’re a Great Mage?”

“Yes. I can open dimensions to travel between worlds, so lifting an entire island is trivial.”

“Lifted an island?”

“When I was on an island at sea, there were just too many annoying people.”

She waved her hand as if she didn’t even want to think about it.

“I don’t really have any attachments to this world. No family, and humans here have only caused me pain, trouble, and annoyance.”

“……”

“But still, if you want to see this world with your own eyes, I’ll fully cooperate.”

“Why?”

For a moment, I didn’t understand.

“Why help me?”

“For the price of ten hamburgers?”

“…That’s ridiculously cheap.”

“And if it’s ten hamburgers every day?”

“…Even then. How can you trust me enough to make this offer?”

“You have a good eye for people.”

My chest sank at her words.

It was the same line I used when assessing people I was producing back at the company.

“Do I look like a Demon King invading this world to you, Kang Minhyuk?”

“No.”

“Then what kind of person do I look like?”

“Someone brilliant and talented enough to open dimensional portals to another world.”

“Yes. That’s one side of me, and it’s enough.”

Rasianne pointed to where I had been standing.

“To be honest, I came here for two reasons. One is to gather mana.”

She plucked a blue rose from the garden.

It came off easily, sparkling like a jewel before flowing down like water.

“Eating ten burgers each time I cross dimensions is a pain. So I use pre-stored mana stones. Think of it… as a battery.”

“You don’t need to translate it into your terms; I understand the situation. And the second reason…?”

“I’m more curious about your world than this one.”

The blue rose became liquid and merged into her arm, glowing.

“I’ve already accomplished enough as a Great Mage, so no matter where I go, people will either praise or try to exploit me.”

“Am I different?”

“I’m not against being praised or used. As long as there’s proper compensation, I’m satisfied.”

Rasianne reached toward the air.

The air parted like a curtain, and she extended her hand beyond the space she opened.

“Subspace?”

“Yes. It couldn’t be opened from there… but here.”

Flash.

She pulled out a golden object glowing from within.

“I have quite a bit of stored gold. If it’s materially no different from Earth’s gold, I can provide it.”

“……”

“Of course, if someone asks where such a large amount of gold came from, it might be troublesome. But if you can handle it…”

“What do you want to do on Earth?”

I took the gold in my hand.

The texture was slightly different from ingots I had held before, but the feel was familiar.

“What do you want to do on Earth?”

“Anything and everything. Just exploring and learning unknown knowledge is satisfying, but it’s better if I have a local aide. For example…”

Whoosh.

A breeze blew from outside.

“If you want to travel this world, I can be your guide.”

“…!”

“We’ll be each other’s travel guide in another world. A local collaborator. How does that sound?”

Rasianne extended her hand toward me.

It was clearly a handshake, and I gripped the gold in my other hand, returning the gesture.

“Even if this were an illusion, a Great Mage crossing dimensions could easily use mind-control or hypnosis spells.”

“In difficult cases, I can, but I don’t use them indiscriminately.”

“Couldn’t you force me to cooperate?”

“Even without magic, rational conversation can lead to cooperation.”

Rasianne smiled, pointing at her extended hand.

“Isn’t that right?”

“…Then.”

I shook her hand.

“Let’s start by speaking comfortably.”

“Mm…”

“Formal speech?”

“No.”

Squeeze.

“Speak comfortably.”

“I meant to suggest casual speech.”

“This is comfortable for me.”

“……”

“Really.”

A short while later.

While Rasianne left briefly to prepare some items, I inspected her room.

A grimoire.

At first, the words were indecipherable.

But after blinking, they transformed into Hangul, suddenly readable.

[…Thus, if one uses magic to cross worlds, there’s no guarantee the space beyond the portal is safe. It could be underground, in magma, or the twisted space could trap your body in walls or pull you forever into subspace. Regarding this…]

It seemed Rasianne had written it herself, filled with careful considerations about dimensional travel magic.

“…So this really is another world.”

I set the grimoire down and picked up another book.

A normal book with illustrations rather than spell instructions.

The moment I touched the illustrations, light erupted from the book.

“…Wow.”

I saw blue fields under sunlight.

By a creek with a working waterwheel, children played, and women in old dresses wandered the fields as if picking grain.

Even the scent of wildflowers seemed to reach me.

Was this the power of magic?

“…Incredible.”

If.

If I had simply been reincarnated or transported here, I might have explored this world.

But one very important question remained.

“Rasianne.”

“Yes?”

“Where’s the bathroom here?”

Other parts of this world might have them, but perhaps her Sky Castle did not.

“Guest bathroom?”

“There’s a shower…”

“Bathroom?”

“…Hmm.”

She scratched her cheek and escorted me with her hand.

“Just over there, sir.”

“That’s a portal.”

“It’s faster to use it over there.”

“……”

I couldn’t help but laugh.

I was somewhat prepared, but I hadn’t expected to go back so soon.

‘If I’d stayed in Korea longer, it’d be different.’

Having just returned from Japan, the environment felt unfamiliar, so I wasn’t thinking about leaving anytime soon.

“When we cross back, then?”

“The magic circle is adjusted. I just need to bring my hand to it to open it anytime.”

“What if someone else comes through?”

“Even if all the Grand Sages combined, they couldn’t breach my castle entrance. They don’t even know I research dimensional magic. Crossing dimensions hides this garden with the circle.”

With the thought of “I can return anytime I want” in mind, there was no rush to make hasty decisions.