The Exchange
Marble.
A mineral form of matter where mana had condensed.
Because it held mana, it was used everywhere, regardless of whether you were a magician or a warrior.
Even high-grade marbles could be recharged, so the demand never stopped.
But there was one decisive flaw.
The absolute scarcity of marble supply.
If we used marble, we could commercialize technology that would match or even surpass every modern invention on Earth.
The problem was that marble had no supply.
Only a small portion of the upper class could afford it.
Why am I explaining this now?…
“Aurora: Marble for sale.”
I’m selling to the highest bidder.
500 gold.
1,000.
1,200, please.
The moment I posted the sale, comments flooded in almost instantly.
I knew roughly what the value was from browsing the exchange, but I never expected such an immediate reaction.
And… the prices were skyrocketing.
The highest bid so far had been 2,300 gold.
And the gallery reported that the middle-class salary was only 500 gold.
If the middle-class salary was one million, that would be… 4.6 million?
Was one marble really worth 4.6 million?
The value felt dangerously high.
Maybe it was like selling a germanium bracelet on Earth that offered huge health benefits.
Of course, it had been a lie on Earth, but in fantasy anything was possible.
Well, at least it looked like it wouldn’t go any higher than this.
The instant I sent a trade request to the highest bidder.
“4,000 gold. Want to trade?”
On a 100-gram rock, dropping 800 million…
No way. A customer had appeared.
“Are you insane? Even a grade-two marble isn’t 4,000.”
“Did you lose your marbles? 4,000 would buy you ten grade-three ones.”
The reaction was clear—he had overbid massively.
But… from the seller’s side, it didn’t matter.
I immediately accepted the 4,000-gold trade.
When I gripped the marble and tapped “accept,” it vanished in a flash.
“O…”
The exchange window instantly updated.
[Administrator inspection in progress. Please wait a moment.]
The system where you first sent the item to the administrator, got verified, and only then completed the trade.
Back then I had wondered if the administrator, nicknamed Jutak, had multiple bodies.
How could he handle all this alone?
As soon as that thought crossed my mind, a message appeared.
[Inspection complete.]
Gold rained in front of me.
Plop.
“Eh?”
Instead of the dull thud I expected, something paper-like and weightless landed.
On the white counter, the visible text read…
“What is this even saying?”
The numbers were completely different.
But the meaning was clear enough.
“1,000 gold each, four of them?”
Probably they used checks instead of pure gold for convenience.
One of the mysteries of this other world had been solved.
That was how I made money so easily.
The marbles were still plenty left, so I started selling to others.
(Whisper) Truth Scholar: You’re selling marbles? Maybe you should stop.
My hand froze the instant I tried to trade with the next highest bidder.
I would have proceeded with anyone else, but because it was the Truth Scholar who had helped me so much, I naturally stopped.
(Whisper) Aurora: Why?
(Whisper) Truth Scholar: Hmm… I guess you don’t know. Let me explain.
There was a brief pause, then the Truth Scholar poured out the words at lightning speed.
(Whisper) Truth Scholar: Basically, marble is a multi-purpose material.
Magic, swordsmanship, elemental magic, summoning, holy power—every single field.
It was no exaggeration to say it could be used anywhere.
That part I already knew.
But everything after that was new information.
(Whisper) Truth Scholar: The problem is that anti-social forces also use marble.
And the marble you sold is high-grade.
There are only a few hundred in the entire world.
If you sell too many, the rarity drops and anti-social forces can easily obtain them.
It could spark a new war.
When I read that “spark a new war” line, I froze.
I hadn’t expected such value.
If I was lucky, it was only because I had sold one.
Wait… what if the person I sold to belonged to an anti-social force?
An amount of money far beyond what anyone else would invest.
And an anonymous user, not even the Truth Scholar.
Cold sweat poured down my back.
Was I accidentally helping an anti-social force?
But…
(Whisper) Truth Scholar: Thankfully the Tower retrieved it this time, so no need to worry.
I just wanted to warn you to be careful when selling other Deep Sea items.
You have that much influence.
The Truth Scholar signed off and disappeared from the chat.
“Whew… at least that was lucky.”
I let out a sigh of relief that it hadn’t gone to someone else.
My complicated thoughts slowly cleared.
Talking to the Truth Scholar taught me two things.
First, my influence far exceeded my expectations.
Second, the Truth Scholar was high up in the Tower.
The way he said “our” Tower and casually gave me the ancient item “Construct” said it all.
He even understood magic deeply.
‘… Maybe I should give him a gift.’
What did high-ranking Tower members like?
After thinking it over, I figured he’d enjoy exploring the Deep Sea.
Well, that was something to think about later.
Right now, I had to do something.
4,000 gold. On Earth, that was about 800 million won.
Of course, gold couldn’t be used in the Deep Sea…
“But the gallery accepts it.”
The exchange had countless items.
Of course, there were tons that would help my survival.
The problem was… I was still in the Deep Sea.
If something wasn’t overwhelmingly superior, it probably wouldn’t matter.
“What I’m lacking right now…”
I kept the exchange window open and started listing the annoyances one by one.
Just throwing a blanket over the hammock made my back feel like it would snap.
No bathroom, so I had to walk far.
To shower, I had to catch a Cyclops, wash with water that smelled faintly of blood…
“… Is this really how it’s supposed to work?”
I had been so focused on survival that these issues had been pushed aside.
But life in the Deep Sea was far from ideal.
I turned my hand toward daily necessities for tools.
“First, a mattress…”
I picked three convenience items.
The problem was that I had almost spent all my money.
I could afford three items for 800 million, sure.
But there was a reason.
First, the mattress wasn’t that expensive.
I bought a very comfortable one for 15 gold.
The real issue was the bathroom for hygiene.
On Earth it was nearly impossible.
I bought a Bluetooth shower and an automated toilet with flowing water and automatic waste incineration.
My money vanished.
Roughly 200 million for the shower and 500 million for the toilet.
It felt like I had spent too much, but thinking about how awful the past had been, it was necessary.
One experience washing in purified blood was more than enough.
Since the structure was unforgiving, the items I bought with a clear conscience…
“Oh! It’s coming out!”
A shower that produced water without a connected hose, using my mana.
Seeing it brought back memories of my early days learning magic.
I had just started and believed in the Truth Scholar, so I tried water magic without a second thought.
Splash!!
And I was hit with a water bomb.
Because I couldn’t control it, dropping water like a filter was impossible.
Those days of drinking blood with tears in my eyes…
But that was over.
The shower only produced water, so I could even drink it.
It would be even cleaner than modern versions.
The automated toilet, another product of magic engineering, was kept outside the hammock.
The last item, the mattress.
“Ah… I just want to lie down and rest.”
It was so plush that it instantly shattered my intention to go out for a quick scout today.
It was so comfortable I thought magic engineering was involved.
I was about to lie down and scroll the gallery when—
Wing. Wing.
Beep!
“… Wake up?”
Wing.
Absoluzon shook its robotic arm in front of me, clearly demanding I get up.
It looked a little like a cat telling me to hurry up.
I moved my lethargic body and sat up.
“I’ll be right back.”
Wing.
Absoluzon waved its hand, bidding me farewell.
I waved back and headed out.
This trip was just a simple scout, so nothing major should happen.
***
…Or so I thought.
Scratch. Scratch.
The dark scythe dragged along the floor with an eerie sound.
I peeked around the wall.
A black hood wrapped in shredded leather.
Thick black smoke filling the surroundings.
And… a glimpse of a grotesque skull.
The gatekeeper of the weapon factory, my next destination.