In the end, Reinhard spent a single night on Hourai Island.
The next morning, the two men dove straight into their work immediately after breakfast.
"I’d like to incorporate Lorelei’s movements into the skeleton-frame golems."
"Hmm... if that's the case, perhaps if you tried this..."
Reinhard offered his advice to Jin, while Jin shared his own expertise in return.
"By adding chromium and nickel to iron, you can create an alloy like this."
"Hmm. So these are called chromium and nickel? I’ve seen them occasionally, but they were always being discarded as waste."
Jin guided Reinhard through the process.
"Alright, let’s do this here."
"And that there."
As a result of their collaboration, the repairs on the Schwarzritter were finished by noon, and Jin also completed his specialized underwater golem, the Mermaid.
"Hmm. It doesn't look like a mermaid type will be of much use on land."
"I apologize, My Master."
Mermaid 1 bowed her head. Jin quickly consoled her.
"No, I didn't mean it that way. From now on, I want your kind to cooperate with the Navy to handle underwater development and exploration."
"I understand. I'll do my best."
With the upper body of an adult woman and the lower body of a fish, the Mermaid golems would eventually number one hundred. They would go on to be highly active in the seas surrounding Hourai Island.
Meanwhile, the Schwarzritter was undergoing its own transformation.
"How are you feeling, Noir?" Reinhard asked during the final adjustments.
"Yes, quite well. However, since the output balance has changed, I believe it will take some time for me to grow accustomed to it."
By using 18-12 stainless steel for much of its construction and reinforcing it with Hardening magic, its durability had doubled compared to its previous steel frame.
While it didn't utilize Sea Dragon leather, Jin had used Hourai Island's high-quality magical fiber for the internals, giving it an output equivalent to his Army golems.
Furthermore, with the installation of a Jin-style shield case as a countermeasure against Master-Slave Rewrite Magic, the golem had truly been reborn.
Finally, since the control core had been replaced, its speech was now fluent. Reinhard decided to name this newly improved Schwarzritter "Noir," meaning black.
They decided to have lunch on Kunlun Island with Elsa and the others.
Jin had sent word ahead, so a meal for four was ready when they arrived. During the meal, Jin explained to Reinhard that Mine's previously extreme behavior had been the result of the magic Seduce. Though things were a bit stiff at first, the tension soon dissipated, and they were able to converse normally again.
"So, you've managed to settle in, Elsa."
"Mm. Now, every day, Mother teaches me things. Like cooking and sewing."
"Elsa made this soup, didn't she?"
By now, Jin could usually tell the difference between Elsa’s and Mine’s seasoning.
"Mm. Jin-nii, you can tell?"
"Of course I can. I get to enjoy it every day, after all."
Elsa smiled happily at his response. Watching her, Reinhard felt certain that he had made the right choice by leaving her in Jin's care.
After the meal, Jin turned to Reinhard.
"Reinhard, give that to her."
Understanding immediately, Reinhard pulled an object from the luggage Reiko had brought.
"Here, Elsa. You forgot this."
"Ah, Non..."
It was Non, the Japanese doll Jin had made. Reinhard had brought the doll Elsa had been forced to leave behind. She took it into her hands.
"Thank you, Rai-nii. I'm so happy."
A shimmer of tears appeared in her eyes as she accepted it.
"Thank you very much, Lord Reinhard," Mine added with a bow.
Eventually, Jin and Reinhard found the time to sit down and discuss the future in detail.
"At any rate, you need to be careful, Reinhard. Your guards were killed, after all."
"Yeah, this incident really hammered that home. Even the Schwarzritter was defeated once. I can't afford to be overconfident."
For now, a dedicated Secret Mobile Unit—the SP—was assigned to watch over him.
"I just received a new report. It seems the Celuroa Kingdom and the Kingdom of Franz are both overwhelming their enemies."
This was information Jin had just received from Laojun.
"I'll refrain from asking exactly how you get your information, Jin. Regardless, I'm still a diplomat for the Shouro Empire; I can't go around hiding forever. It would reflect poorly on my country’s prestige."
"..."
"In any case, now that it's come to this, I'll have to ask the garrisoned troops to escort me back home."
Jin nodded, though still somewhat worried, as Reinhard explained that he would request an escort of a platoon or company rather than just a few men.
"Rather, I'm worried about you, Jin. You should avoid doing anything conspicuous for a while. There’s a high chance you'll be targeted by both nations—or at the very least, viewed with suspicion."
"Ah... I suppose that’s true."
"For you, getting to the Shouro Empire is probably a simple matter, right? It looks like we won't be able to travel together, but you must come visit. I'll be waiting."
Reinhard spoke with a touch of regret. Jin was also interested in the Shouro Empire, a major power outside the Allied Kingdoms, and he was curious about the artifact from before the Great Magic War that Reinhard had mentioned.
"Yeah, I'll head over there soon. You still have your manacam, right?"
"Yeah. Fortunately, it was left at the inn, so the Unifilar didn't get their hands on it. Though they did take my Protect Ring."
The captured Unifilar members hadn't had Reinhard's Protect Ring on them. It was currently at the bottom of the river along with the branch manager.
Hearing that, Jin pulled a ring out of his pocket as if just remembering it.
"Right, I almost forgot. This is a new Protect Ring. It's the same as the one you had."
Reinhard accepted the ring Jin handed him.
"Jin, thank you. I'll take it gladly. Well then, I should probably be on my way."
Because of the time difference, there was no real need to rush, but Reinhard didn't quite grasp that and insisted on returning.
"Claude will be worried since I stayed out without saying anything."
"True. Then, let me see you off as far as Jiron."
Jin stood up with Reinhard and walked toward the Warp Gate. Noir and Reiko followed close behind.
The transfer was instantaneous. They emerged inside Falcon 1, which was standing by in the outskirts of Jiron.
Once they stepped outside Falcon 1’s stealth barrier, the town of Jiron was visible in the distance.
"Now that I think about it, it's still just past noon here. You'll have to explain the reason for that next time we meet."
With those parting words, Reinhard said his farewells.
"Yeah, I will. Well then, until next time."
"Mm. I'll be waiting in the Shouro Empire."
Reinhard started to walk away, but he suddenly stopped and turned back.
"Jin, I'll tell you one thing. That artifact I mentioned... it's a giant golem."
"Huh?"
Having been told the one thing he was most curious about, Jin stood there with his mouth hanging open.
"Haha. Knowing you, Jin, you'll probably make something similar—no, something even more incredible. There's not much point in keeping it a secret anymore."
With that, Reinhard finally set off toward Jiron. Jin turned to Reiko.
"Reiko."
"Yes, Father."
"Watch over Reinhard until he safely reaches the town and reunites with Claude."
"Understood... But please be careful as well, Father."
Deeply concerned for Jin's safety even as she obeyed, Reiko vanished using Stealth and secretly trailed Reinhard. Since Sage and Cosmos were also with her, he could rest easy.
Jin settled in to wait inside the Falcon.
Until Reiko returned, he found himself occupied with thoughts of the giant golem Reinhard had described.
In general, the larger a moving object becomes, the more sluggish its movements. This is due to the relationship between structural strength and inertia.
To stop a swinging arm, one has to fight inertia. If you push a frame past its limits to overcome that inertia, the arm will snap.
While bending strength—one measure of an object's durability—is proportional to its cross-sectional area, its mass is proportional to its volume.
In other words, strength increases by the square of the object's size, while inertia increases by the cube. As things grow larger, their strength becomes insufficient to support their own mass.
In that sense, the human scale was perfectly balanced for movement.
"But then there’s the dragons and the Hekatonkheir..."
Those creatures were remarkably fast for their size.
"It's possible their density is low, making them light. It would be consistent if I assume their low structural strength is reinforced by magical power."
The more he thought about it, the more he felt that had to be the answer.
"So their weight only increases by the square of their size."
It was a highly simplified theory, but it was likely close to the mark.
"If it were fifteen meters tall, for a human... let's see..."
Jin was 160 centimeters tall and weighed 52 kilograms.
A fifteen-meter golem would be 9.375 times larger. Since volume is the cube of the scale, it would be 824 times larger, weighing approximately 42.85 tons.
If weight only increased by the square, however, it would only weigh 4.57 tons.
"If I could keep it around five tons, it might actually work..."
Jin, too, was a man who grew up yearning for giant robots.