"…Your Grace, could I have about ten grams of adamantite?"
Jin, who had been focused on Tia’s maintenance, turned to address Duke Blue with his request.
"Duke, if you would. The royal family will bear the cost," Ernest XVII added. Even in this era, adamantite remained prohibitively expensive.
Compared to 64 light silver, which had become more common after Jin created refining magi-devices four hundred years ago, adamantite was produced in tiny quantities and was notoriously difficult to refine. The market price sat at roughly 7,000 Toll per gram—equivalent to approximately 70,000 yen.
The ten grams Jin requested were worth roughly 700,000 yen, a cost Ernest XVII was quick to offer to cover.
"No, Your Highness, please do not concern yourself with the price. It is a rare enough privilege to witness the craftsmanship of the Magi Craft Meister—and to see the internal structure of an automaton that could rightly be called an artifact."
Duke Blue clearly possessed an abiding interest in magi-craft herself.
Once Jin received the ten grams of adamantite, he set to work.
"Plating."
He began applying the metal to the sliding sections of the joints.
The specific gravity of adamantite is 19.3. Ten grams was barely the size of the tip of a pinky finger. However, it was one of the world's hardest metals—surpassed only by molecularly compressed adamantite.
As was his usual technique, Jin plated the sliding surfaces to eliminate gaps and ensure the joints were almost entirely resistant to wear. While the skeleton was already made of durable five-half nickel steel, this treatment vastly increased its longevity.
"The magi-circuits should be fine with simple repairs."
Mithril is highly resistant to oxidation. Since the components had been kept in a sealed environment, degradation was minimal. However, in sections that were subject to frequent bending, metal fatigue had made the fibers brittle, so Jin restored them to their original state.
"Control core is okay. All major magi-devices are perfectly functional."
It was a testament to the quality of the work Jin had done four hundred years ago. Though he was praising his own past self, the thought brought a smile to his face.
"The magical muscles, however… they’ve definitely seen better days."
This was unavoidable. No matter how superior biological materials were, four centuries was an immense span of time. The concentration of free ether in the Kingdom of Egerea wasn't particularly conducive to the preservation of such materials, and magical muscles were ultimately consumable parts.
Furthermore, Tia's magical muscles were made from sandworm hide. They couldn't hold a candle to the Ancient Dragon hide used in Reiko’s construction.
"…How to handle this?" Jin mused.
Back on Hourai Island, he had unrestricted access to precious materials—even leather processed from the molted hides of Ancient Dragons. Over the last four hundred years, Laojun had been collecting these rare materials from the frigid northern reaches.
Of course, they didn't over-harvest. Jin abhorred such practices. Instead, they had actively protected the species; the total population of confirmed Ancient Dragons currently numbered thirty. Given that a survey three hundred years ago had counted only twenty-five, their numbers had increased by twenty percent.
Simultaneously, the population of Frost Dragons, which scavenged the discarded hides of the Ancient Dragons, had grown from 220 to 240.
This growth was the result of efforts to lower the mortality rate of the larvae through minor environmental improvements. Even the Ancient Dragon, the pinnacle of life on Ars, is helpless in its larval stage. They are oviparous, laying eggs in the spring that hatch in the autumn.
The research of Goose and other scholars had revealed that their survival through the winter depended entirely on how much they could grow before the first frost. Once they discovered the larvae fed on freshwater fish, Laojun had begun farming and increasing the local fish populations in the far north to improve their food supply.
Returning to the task at hand.
While Jin couldn't use Ancient Dragon molts here, he could certainly use the ground spider silk that was standard on Hourai Island. It was now farmed in several locations outside the island and had become a cornerstone of the Nord Federation’s industry.
With Duke Blue's permission, Jin took two bundles of ground spider silk from the workshop's shelves and began transmuting them into muscle tissue.
First, he twisted the fibers together to thicken them, then used Fusion to bond the ends, shaping them into proper muscle bundles. The entire process took a mere fifteen seconds. It was the effortless skill of a man who had built thousands of golems and automata.
Jin produced a total of 100 sets. Toward the end, he began processing them in groups of four, completing the entire batch in about ten minutes.
Duke Blue and Ernest XVII watched in stunned silence, their mouths agape. Even Lordtoss seemed to have lost his voice.
"Right, let's start swapping these out."
"I will assist you, Father."
With Reiko’s help, the pace of the work accelerated even further. The 100 sets of muscles were installed into their proper places on the skeleton and connected to the magi-circuits.
For reference, a human body is said to have over 600 individual muscles. Jin managed the same range of motion with only 100. By categorizing their functions and having them share roles, he reduced the total number to simplify the control logic.
Crucially, "human-like" movement was not sacrificed in the process. This was the true brilliance of the Adriana-style logic. As a side note, Reiko possessed approximately 300 muscles, while the standard golems of Hourai Island had about 200, allowing for even more fluid, lifelike articulation.
"That’s the last of them. The skin is still in good shape."
To enhance their durability, Jin applied Strengthen to both the magical muscles and the magical skin. Finally, he performed a fine-tuning of the control core and other magi-devices to account for the new muscle density.
"Tia, how do you feel?" Jin asked once she was dressed and reactivated.
"I feel wonderful, Jin-sama. Everything is so much smoother. Thank you very much."
"Good to hear."
Jin then turned to give his report to Ernest XVII.
"Your Highness, the maintenance of Tia is complete.…Your Highness?"
"…Hah! Oh, yes, excellent work. Thank you, Jin-dono. My sister will be delighted. You have my deepest gratitude!"
Ernest XVII had been staring in a trance-like state, only snapping back to reality at the sound of Jin’s voice.
"Your Highness, I am profoundly grateful for this service to my body. I look forward to continuing my service to the Princess," Tia added, bowing her head to the prince who had arranged the repairs.
"Yes, of course. I'm glad to hear it."
By then, Duke Blue had also regained her composure.
"Jin-dono, that was a magnificent display of skill! You have my thanks for allowing me to witness it!" she exclaimed, clearly in high spirits.
The group returned to the drawing room. Ernest XVII immediately brought up the matter of Jin’s compensation.
"Tia mentioned that a Magi Craft Meister prefers materials over gold as a reward. Is that correct?"
"…Generally, yes. I find rare materials much more satisfying."
"I see."
Ernest XVII considered this for a moment before speaking again.
"The materials found within the Kingdom of Egerea may not be particularly rare to you… but how would ten standard-grade Elradrite suit you?"
Elradrite was the common name on the Lauren Continent; its formal name was Mityanite, and its mineral classification was Univasium. It was a mineral that did not naturally occur on Ars, harvested instead from ancient meteorite impact sites. Both the names Mityanite and Univasium were derived from that extraterrestrial origin.
"No, I would be quite embarrassed to take something so valuable. How about 100 kilograms of 64 light silver instead?"
"Is that truly enough?"
In the past, the price of 64 light silver—or titanium—had been astronomical. But since Jin had introduced refining magi-devices four centuries ago, the price had plummeted to roughly 20 Toll per kilogram (about 200 yen), making it slightly cheaper than aluminum in modern Japan.
Jin calculated that the work had taken barely an hour. Since Duke Blue had provided the workshop and some of the materials, he felt that receiving the equivalent of 20,000 yen for his labor was perfectly fair.
"Yes, 64 light silver is very versatile."
"Very well. If that is what you wish, Jin-dono, then so be it.…Duke, might I ask you to provide it from your stores for now?"
Ernest XVII requested that Duke Blue pay Jin from her own stock, promising the royal family would reimburse her later.
In the end, Jin walked away with 200 kilograms of 64 light silver as his reward.