At the conclusion of their meeting, Jin informed the Empress that he would be "returning to Kunlun Island for the time being."
"I see. With that airship of yours, traveling back and forth is quite simple, isn't it? I look forward to the day we meet again."
With those parting words, the Empress saw Jin and his companions off.
＊ ＊ ＊
At 3:00 PM, with Barrow and Belle seeing them off, Jin, Reiko, and Elsa took flight aboard the Konron 2.
They immediately began a steep ascent.
Once they reached an altitude where they were completely invisible from the ground, Jin activated the transporter he had received from No. 700672.
The marker was set to the courtyard of the laboratory on Hourai Island. Locally, it was around 9:00 PM.
As the Konron 2 touched down in the courtyard, which was illuminated brightly by magi-lamps, an unexpected figure greeted them.
"Hey there, Jin, Elsa! Welcome home. I’ve been waiting for you!"
"Saki?"
"Saki-nee?"
"Welcome home, My Lord. Saki-san has been assisting me with the investigation into the physical properties of our materials."
Jin nodded at Laojun's explanation. He smiled, thinking it was just like Saki to dive into such work with glee.
They headed straight for the workshop. Rather than the ground-floor workshop Jin usually occupied, they went to the research lab on the second floor.
"We tested ground spider silk, Sea Dragon wing-membrane, crystal, cubic zirconia, gold, mithril, 64 light silver, and adamantite," Saki reported.
"Hmm, those are solid choices for testing."
They had prioritized materials known for their strength and durability.
"In contrast, the substances we tested them against were Gigant Peeder fluid, Giga Ant fluid, and the dissolution fluid from the 'Copy.'"
"Wait a second. How did you get the dissolution fluid from the 'Copy'?"
Laojun provided the answer.
"My Lord, at that time, the enemies had discarded everything except for a single gold container. I took the liberty of secretly securing about half of its contents."
"I... I see."
"It was all for the sake of research."
It sounded like a line straight out of a mad scientist's manifesto.
Jin decided to let the matter rest for the moment and urged them to continue.
"The material with the highest chemical resistance was the ground spider silk. Among the metals, adamantite was the most impressive, though even it was slightly corroded by the Gigant Peeder and Giga Ant fluids."
"I see..."
"It’s quite fascinating—almost like 'Earth overcomes Water,'" Laojun’s voice chimed in.
He was referring to how the monsters that dwelt in the earth had proven superior to materials derived from the water.
"Earth overcomes Water" was a concept from the Five Elements philosophy of ancient China. It held that Earth overcomes Water, Water overcomes Fire, Fire overcomes Metal, Metal overcomes Wood, and Wood overcomes Earth.
Having seen the concept in various novels and manga, Jin was somewhat familiar with it.
"Regardless, ground spider silk is too soft to be used for structural frames or armor. We’ll need to find something better."
"Hmm. It’s not like a better material will just fall into our laps, though."
"Jin-nii, why not try asking No. 700672?" Elsa suggested.
"...Ah, good point."
To be honest, Jin was reluctant to keep leaning on him every time a problem arose, but when he considered the possibility of more dangerous monsters lurking in the ruins of the former Leonard Kingdom, he couldn't afford to be proud.
"I guess I’ll go ask him..."
In truth, powerful monsters and magical beasts were far more common in the north. He held out hope that No. 700672, who resided in those northern reaches, would possess a wealth of information.
"Are you going to see No. 700672 now, Jin?" Saki asked.
"Yeah. I also want to thank him again for the transporter. I'll head over tomorrow."
＊ ＊ ＊
The following morning.
Jin and his companions finished a hasty breakfast.
"I'd love to go too... but I'll pass this time," Saki said with a hint of regret.
"Understood. That might be for the best. Reiko and I will handle it."
"Mm. Have a safe trip."
Seen off by Elsa and Saki, Jin headed to the Warp Gate room with Reiko. On the way, he picked up some Persica juice that Laojun had prepared as a gift.
The two then stepped through the Warp Gate.
Emerging inside the Heavenly Ship, they were greeted by Smith 45 and Smith 46, who were standing guard.
"Welcome, Master."
"There are no abnormalities to report."
"Good work."
After the brief exchange, Jin placed his hand on the door to the White Room. It recognized him and slid open.
"Jin-sama, Reiko-san, welcome. Are you here to see Father?"
"Yeah. Hello, Neige. I have something I'd like to ask him today."
As he spoke with Neige, No. 700672 appeared.
"Ah, Jin-dono. Welcome."
"Good morning."
Jin handed over the Persica juice he had brought.
"Oh, thank you. The last batch was just about to run out."
"If that's the case, I’ll make sure to have it delivered regularly."
"That would be most appreciated."
Since the Smiths were stationed outside the room, Jin figured they could bring the juice to the door for Neige to collect at her convenience. The arrangement reminded him vaguely of a milk delivery service.
"So, what brings you here today? I presume you have something on your mind."
Jin nodded at No. 700672's sharp intuition.
"I do. Actually..."
Jin explained the situation regarding the ruins in the former Leonard Kingdom and the monsters emerging from the depths. He also mentioned how Reiko's skin, crafted from Sea Dragon wing-membrane, had been dissolved.
"Hmm..."
No. 700672 listened to the end, occasionally interjecting with a question, before folding his arms in deep thought.
After nearly a minute of silence, he uncrossed his arms and spoke.
"It is true that many of the creatures dwelling underground are exceptionally powerful. They have evolved magically to survive in such hostile environments. It stands to reason that they could dissolve even the wing-membrane of a Sea Dragon."
Jin nodded. The explanation made perfect sense.
"I suspect that in addition to ordinary acidic properties, their fluids use free ether to weaken the molecular bonds of the materials they touch."
"I can see that being the case."
"Now then, enough with the preamble... It is winter now, is it not?"
"Eh? Yes, it is."
"Hmph. That is fortunate. Jin-dono, are you familiar with the Ancient Dragon?"
Jin searched his memory but came up empty.
"No, I’m not."
"I see. It is a massive dragon said to inhabit the northernmost reaches of this continent. It is likely the pinnacle of all living organisms on this planet."
"The pinnacle of all living things?"
"Indeed. It is a biological creature, of course, and thus can be killed. However, they are fundamentally docile and never venture south. They dwell in the lands of extreme cold, subsisting on high-concentration free ether."
It sounded like a formidable creature indeed.
Generally speaking, on the planet Ars, carnivores were stronger than herbivores, and magical beasts that consumed free ether were stronger than carnivores. This strength manifested in various ways, such as extreme longevity or physical durability.
"Regarding that Ancient Dragon—it molts during the height of winter. If you can obtain that shed skin, it will serve as one of the strongest materials in existence."
"I see! Thank you very much!"
Grateful for the invaluable information, Jin bowed his head.
"Will you go searching for it?"
"Yes, that's the plan."
"I need not tell you to prepare for the cold, but be warned: there is another powerful magical beast that dwells at the world's edge. You must remain vigilant."
"Another magical beast?"
"Indeed. It is called the Frost Dragon. It is known to possess the habit of consuming the molted skin of the Ancient Dragon."
"That... that complicates things."
That meant a confrontation was highly likely.
"The population of Ancient Dragons is small. There are likely fewer than ten in existence. By contrast, I suspect there are three times as many Frost Dragons."
"Then a run-in is almost guaranteed."
"I believe so. Therefore, ensure your preparations are flawless."
"Based on the name, I assume the Frost Dragon uses freezing magic?"
"Indeed. It is said they can freeze over a small volcano. Go with caution."
"I understand. Thank you for everything. I'll come back to report once we've successfully retrieved it."
"I wish you success."
With that, Jin returned to Hourai Island.