A voice of disbelief rippled through the onlookers.

“It’s not just a one-off miracle created by a master like Jin Cheon-hee? You’re saying mass production is actually possible? I can’t believe it!”

Jin Cheon-hee merely smirked.

“No problem at all. We do have to invest significantly in facilities and manpower, but it is fully within the realm of possibility.”

It was the same principle as the White Qilin Divine Elixir: executing a miracle within the strict limits of what human hands could achieve.

Jin Cheon-hee sprawled out comfortably on the floor and looked up. “So, are you going to take my hand or not?”

At those words, Sama Hyeon couldn’t help but laugh. This blue-eyed madman was still worrying about whether he would stray from the path of humanity. He was strong and thoughtful, yet precariously balanced.

Wasn’t the answer decided from the start?

“Watching the opera yesterday… I saw Hye-ah holding both my hand and Hyung’s hand.”

“Yeah. She did.”

“I wonder if it’s really possible to become the Golden King by taking the hard road instead of the easy one… But yes. Yeah.”

Sama Hyeon extended his hand toward his brother lying on the floor.

“The answer was already decided, Darling~”

“Right.”

Thus, the older brother grasped his younger brother’s hand.

Even if this ends at the edge of hell, Sama Hyeon thought, the path taken with this brother will be quite enjoyable.

He didn’t know if he could truly become the Golden King by stubbornly sticking to the moral high road. But really, wasn’t it enough if it was fun? As long as these blue eyes led the way and his brother held his hand, he would always remain the youngest, Hyeon.

In his past life, amidst the infinite library of YouTube, he had seen many things. Among them was a process he had skimmed over without much thought, now recreated through the clarion recall of the Xuanayuan Divine Art.

The objective was plate glass.

He intended to utilize the float glass process invented by Sir Alastair Pilkington of England.

First, melt tin to a liquid state. Left alone, liquefied tin forms a perfectly flat surface due to gravity. On top of that, liquefied glass is slowly poured. Since tin is heavy and glass is light, the glass floats atop the molten metal like oil on water.

Naturally, as it cools, it forms plate glass with a perfectly smooth surface.

“The size of the glass is determined by the dimensions of the container holding the tin. If the facilities are sufficient, we can make it as big as we want. Of course, making it reallllly huge might be tough, but moderately large is fine.”

“Wow… This actually works?”

“Right. Making plate glass this flat is impossible unless you’re someone like Yoo Ho. But if we make mirrors with this, they become incredible treasures.”

Now, shall we make a fortune with this?

While abusing the Otherworldly Cheat or whatever one called it, he might as well take it a step further and rake in the cash.

“Usually, mirrors are mostly hand mirrors or barely big enough to see one’s face. The metal reflectivity isn’t great, and the technology for perfectly smooth surfaces didn’t exist in the first place.”

A full-body mirror. #Let’sGo.

Sama Hyeon tapped rapidly on his abacus at Jin Cheon-hee’s plan. “First, the price per piece should be one thousand taels of gold. Production cost… about five taels? Facility costs… five hundred taels. We’re going to profit immensely, aren’t we?”

Ah, do you not know? This is the power of the Earthling cheat.

You Central Plains bastards. You think I only know how to make Penicillin and Streptomycin? If I set my mind to it, I can make glass mirrors too!

Of course, squeezing Earth memories out of his brain like a washing machine on the spin cycle using the Xuanayuan Divine Art had almost given him a brain cramp. But he had done it.

“First,” Sama Hyeon calculated, “if we present it to His Majesty the Emperor, and then to His Highness Prince Ju, the trendsetter, the game is already over~”

Where did you learn the phrase ‘game over’? Are you memorizing whatever Hyung says through self-directed learning?

It was getting a bit scary. This rascal.

“Anyway, do you like it?”

“Of course. You pull it off like it’s cheating. Hyung.”

Sama Hyeon laughed softly, then grew pensive. “Somehow, I felt like the tin laid underneath was like Hyung.”

“What?”

“Because without Hyung, I would have been nothing but a mere shard. Wouldn’t I just be stabbing people in some back alley?”

“Umm…”

Sama Hyeon always spoke of himself humbly, bordering on self-deprecation. However, the future that Sama Hyeon occasionally hinted at contained a version of himself as the Supreme Heavenly Demon, so it was hard to just laugh it off.

Therefore, Jin Cheon-hee gave a different answer.

“Then the current you must be the plate glass.”

“I suppose so. Don’t know if I’m level, though. Even if I’m just a trivial glass shard right now. I know at least that boiling oneself to make someone else stand tall is a difficult task.”

Saying this, he stood up.

Jin Cheon-hee murmured, “Tin…”

Boiling and hardening, boiling again to support and hold someone up. Not pretty or hard like gold, silver, copper, or even steel—just a piece of base metal. Yet, somehow, Jin Cheon-hee liked it.

***

Thus, purely by the hands of artisans, a full-body mirror was completed.

Sama Hyeon and Sama Hye were speechless for a long while, staring at their reflections. They had never seen a mirror with such high fidelity before.

“Wow… It’s clear without any cloudy parts? Benefactor.”

“Ah, do you not know? This is called a [Full-Body Mirror].”

“…”

Kuh, as expected, no one gets the reference.

This was all because he fell into a Wuxia world. If it were a Fantasy novel, it would have been different. Or maybe not. If it were a Dwarf, they might have looked at him with genuinely pitying eyes, saying, ‘Tin? Is that the struggle of a lower race that can’t flatten glass with their bare hands?’

This was why being a stranger—an Ibangin—was hard. Living in someone else’s house was difficult enough; living in someone else’s world was a trial in itself.

Still, even if the two couldn’t catch the meme Jin Cheon-hee threw, they stared at the mirror with obvious delight.

“Hye-ah, I’ll give you one~” Sama Hyeon offered.

“No, Oppa. It’s fine.” Sama Hye waved her hands in surprise. It looked expensive at a glance.

“Things like this should be given to family first. Customer~ The current one is crude. I’ll have an artisan carve a pattern Hye-ah likes on the edges. Anything you want? Like a Black Dragon?”

“…N-No thanks? Do you think I’m some teenage martial artist who likes stuff like that?”

If a Demonic Cultist heard that, their heart might have torn in two.

“That… maybe a Sichuan Tang Clan shuriken…”

Blood Whip Queen Edition, huh.

Hmm, isn’t ‘a teenage martial artist who likes stuff like that’ exactly Tang Ah herself?

The consumer’s mind was a mystery. He thought he should ask Tang Ah to visit Branch No. 2 if she stopped by Hangzhou soon.

Sama Hyeon furrowed his brows slightly. Even so, carving Sichuan Tang Clan shurikens on the mirror edges wasn’t easy, especially since they didn’t know when this trend would die out. Maybe a dragon, phoenix, or qilin would be more timeless.

Eventually, the Golden Blood Hall’s Rising Star reached a conclusion.

“Fine. Let’s carve it. The Blood Whip Queen will last a long time.”

“Wow!”

“I’ll ask for a large moon to be embossed too.”

“Make it red. It’s called a Blood Moon, widely used as a background for the Blood Whip Queen these days.”

…He wondered if Tang Ah received royalties in this era without intellectual property rights.

Indeed. The Gangho’s first High Technology Full-Body Mirror with over 80% reflectivity was slated to be produced as the Blood Whip Queen Edition.

Feeling this would happen since first seeing Tang Ah… bullshit… no one expected this. They were deciding to leave the Blood Whip Queen Edition in the history of the Murim Planet.

“It would be good to send one to His Majesty the Emperor and His Highness Prince Ju as well… For His Majesty, carving a dragon pattern would be best for presentation. For His Highness, a White Tiger or Red Tiger would be appropriate.”

Sama Hyeon tapped his abacus, calculating the logistics of the tribute goods.

“Hyung should have one too, right?”

“Ah, prioritize Master over me. A Qilin pattern would be good, wishing for his longevity. It’s also Master’s nickname.”

“Okay~ Then I’ll take care of making Hyung’s.”

Loanwords poured out of him as naturally as breathing now. Hyeon-ah.

Jin Cheon-hee fell into thought. “I think it could be used for medical purposes too…”

“Like the centrifuge Hyung made?”

“Yeah, yeah. Oh? You know?”

“I saw it written in a medical book that blood components can be separated without the help of a martial artist.”

“Ooooooh!”

He guessed right immediately.

One of the things Jin Cheon-hee was prioritizing in this world was introducing “appropriate technology.” As the Xuanayuan Divine Art reached great completion, memories of his past life were becoming clearer, and thanks to that, various knowledge he had once skimmed past was sprouting like bamboo shoots after rain.

What he felt in that situation was, Wow, I really was living in a flood of information.

He hadn’t felt it when living in modern times, but even morning educational programs delivered dense information. Of course, some had dubious sources due to adult circumstances… but even Instagram ads twisted themselves to explain a product’s principle somehow.

Adding memories from medical volunteer work to that, what came to mind was the centrifuge.

Blood cells and plasma could be separated quickly and easily without borrowing a martial artist’s internal energy. Malaria could be detected like this, too. It was no exaggeration to say the device was invented to diagnose malaria in remote areas without electricity.

Malaria parasites, starting from mosquitoes, burrowed into liver cells and red blood cells to reproduce and destroy. Consequently, red blood cells infected with parasites had a lower density and were separated by a centrifuge, allowing diagnosis using that principle.

Of course, they needed a microscope too. That layer had to be extracted and viewed under magnification.

The person who succeeded in appropriate technology with that centrifuge also made a paper microscope costing only 800 won. Being cheaper than the primitive microscope made initially was an advantage, but having to put the eye very close was a disadvantage. The possibility of getting infected by the pathogen being observed was also cited as a problem—especially in this era.

Plus, various detailed items like small lens beads were needed, and he was looking for a way to make them without exploiting Yoo Ho. This was one of the projects running in the White Qilin Medical Pavilion lab.

It was good for educational purposes. But could it be used for diagnosis? Whether this paper device would surpass the Primitive Microscope (Gangho Improved Ver.) remained to be seen… but he felt he would probably stick to using the Primitive Microscope.

Similarly, he had to rack his brain to see if this glass technology could be used for medical purposes. Whether used or not, technology was a case of “the more the better.”