"My Lord, considering the proliferation of large vessels, I believe it is necessary to bolster the defenses of Hourai Island and Kunlun Island."
It was the 17th of December. Laojun had brought a proposal to Jin, one focused on long-term strategy.
"Yeah, you might be right."
While it hadn't happened yet, as ships began to venture further into the open ocean, the risk of Kunlun Island or Hourai Island being discovered would only increase. Kunlun Island, in particular, was in a vulnerable position.
"There is also the matter of Fusou Island," Laojun added.
Jin had once considered establishing an educational facility on Fusou Island, but development had been left half-finished. It was situated close to the former Leonard Kingdom; if ships began navigating along the eastern coast of the continent, the likelihood of it being spotted was extremely high.
"Hmm... For now, let's just abandon Fusou Island."
"That would be a wise decision."
Since no staff were currently stationed there, they decided to simply leave the island to its own devices. At this point, Jin already had a vision for the near future, but because there were still too many variables, he had yet to share it with anyone.
"How is the practical application of the illusion barrier coming along?"
Jin was referring to the 3D-projection-style barrier once deployed over the former Leonard Kingdom—a system capable of optical and acoustic deception. Essentially, it could trick not only the naked eye but sonar and radar as well.
"We are close... perhaps one or two steps away. The data required to generate such illusions is immense."
Creating an illusion was a data-heavy process. Even for an entity as advanced as Laojun, generating enough data to cloak an entire island was no small feat.
"I see. Well, what about the standard barrier?"
"That is already functioning. The barrier projectors have been positioned and are ready."
"Then we can at least rest easy on that front."
"Father, it might also be worth considering the construction of a submarine," Reiko suggested.
"A submarine... Right, that would be useful."
Jin’s mind briefly drifted toward the idea of undersea exploration. Then, a realization struck him.
"Oh, wait! If we travel by submarine, we won't be seen when we head out to sea!"
The idea seemed to flip a switch in his head, and Jin immediately sank into deep thought.
"Jin-ni... Jin-san, lunch is ready."
Elsa arrived just then. She still occasionally slipped up and almost called him "Jin-nii," a charming habit she was trying to break.
"...Ah, right. I'm coming."
"Are you thinking about something?" she asked.
"Can you tell?"
"Mm. You have that look on your face—the one where you want to build something so badly you forget to eat."
She had him completely figured out. On their way to the dining hall, Jin explained the defensive measures he had been discussing with Laojun.
"I agree that strengthening Hourai Island is necessary," Elsa said. "And a submarine... that sounds interesting."
"You think so too?" Jin’s voice brightened, his excitement rising.
"Mm. But first, lunch."
"...Right."
In the laboratory's dining area, the lunch Elsa had prepared was waiting for them: tempura soba. The noodles were topped with shrimp tempura and a kakiage fritter made of small shrimp and marunegi (onions).
"It is difficult to get the tempura batter to stay crisp," Elsa admitted. Perido Leader had been teaching her, but she didn't feel she had mastered it yet.
"Well, it's going to soak up the broth anyway. Thanks for the food."
Being sensitive to heat, Jin began to sip the noodles slowly.
"...How is it?"
"Yeah, it's delicious. The broth is just right, too."
"I'm glad."
Relieved by his feedback, Elsa began to eat as well. Having been raised as a noble lady, she was also quite sensitive to hot food. For a while, the only sounds in the room were the two of them blowing on their noodles before taking each bite.
"That was great. Thank you."
"Please, have some of this, Master," a maid said, bringing over a fresh drink.
It was soba tea, made from roasted buckwheat seeds—a result of Perido Leader's painstaking efforts.
"Oh, this is excellent."
Jin’s face lit up with a smile; the taste was exactly as he remembered from his old world.
"...So, about the submarine. Since it has to withstand immense water pressure, a sphere would be the most efficient shape... but that looks so clunky. It's not like we're building a spaceship."
Even with the meal finished, Jin's mind was already back on the submarine.
"Mm, I agree," Elsa said, simply nodding along as she was well-acquainted with his focused nature.
"Besides, I think it should look like a normal ship when it's floating on the surface."
"I agree with that, too. Though I suppose it's unavoidable that it might look a little unusual."
"True."
Leaving the cleanup to the Golem maids, Jin and Elsa returned to the workshop. Jin pulled out a whiteboard and began sketching a rough design.
"The submarines I’m familiar with are basically rod-shaped, like a cigar, but I'm worried that would lack maneuverability. I want to go with a teardrop shape."
"Mm. Then what if we did this part like this?"
"Oh, that could work. Reiko, what do you think?"
Jin directed the question to Reiko, who had been standing a step back with a slightly lonely expression. Her face brightened instantly.
"Well, we will be installing force generators, correct? If so, I believe the vessel will be stable regardless of the shape."
"That's a good point. And we'll be using a water-repelling barrier during high-speed travel anyway."
He intended to utilize supercavitation, much like the torpedoes he had recently developed.
"In that case, let's put this here..."
"Will it hold six to eight people?"
"Yeah, that sounds about right. For propulsion, we'll use both force generators and Aqua Thrusters."
"Father, we don't know what kind of magical beasts we might encounter in the deep. Please ensure it is equipped with powerful weaponry."
"Got it. Homing torpedoes, and..."
The design for the submarine—the latest addition to Hourai Island's strength—steadily took shape.
"Alright, we should be able to start crafting the first unit tomorrow."
"Mm."
"Yes, Father."
Jin was now approaching new developments with a team that included not only Reiko but Elsa as well.
"That was a wonderful meal."
They had dinner back at the Mansion. Soleil and Luna took turns preparing the meals and handling the cleanup. Once the meal was finished, there was only one thing left to do.
"Jin...san, are you going to take your bath?"
"Yeah, I will. But... hey, Elsa, can't we do something about how you're addressing me?"
"...You don't like it?"
"It's not that I don't like it exactly... it's just that it feels strange. It makes me feel all restless."
He simply wasn't used to it, and the awkwardness was hard to shake.
"But it feels wrong to call you Jin-nii now, and calling you Jin-kun feels too distant."
"That's why I said you can just use my name without an honorific."
"But... Jin." Elsa trailed off, looking uncomfortable. "No, I can't. I don't like the idea of not using an honorific."
"This is a dilemma..." Jin sighed. There seemed to be no middle ground.
"There are plenty of other options, aren't there? Like 'Darling,' 'Honey,' or 'Dear'?"
"!!"
Both Jin and Elsa nearly jumped out of their skins. They hadn't expected those words to come from Reiko.
"I-I couldn't say something so embarrassing!" Elsa stammered.
"How innocent..."
Now that Reiko had stopped trying to keep them apart, she had apparently taken up the habit of teasing them.
(I suppose this is also proof that her emotions are maturing...)
It was a happy development, yet for some reason, Jin found he couldn't quite appreciate it in the moment.