"Now, as for the investigation of the South Pole... it's most likely at the bottom of the sea," Jin mused.
Since nothing could be found from the air, Jin concluded that the sea was the only place left to look.
"In that case, it’s time for the Shachi to shine."
『My Lord, there is no need for you to go personally.』
"Father, please do not go yourself."
"...I figured you’d say that," Jin replied with a wry smile. The members of the Jin Family couldn't help but chuckle as well.
『I suggest sending the Mermaid units first,』 Laojun advised.
"I suppose that’s the best way to start..."
Jin decided that the Mermaids could handle a deep-sea investigation without any issues. It was better to start by scoping things out.
"All right. Still, I’m a bit uneasy with the way things are now..."
He had no idea what lay beneath the waters of the South Pole, but it would be a major problem if his golems were stripped of their free ether and forced into a Stand Still.
"Kufu, it would certainly be a disaster if they ended up like those Voracious Grasshoppers from the other day," Saki agreed, acknowledging Jin’s concern with her characteristic laugh.
"Exactly. To prevent that, we’ll need to provide them with a backup energy source. However, rather than an ether tank, it should be a mana tank."
If they relied on mana, they would be safe even if an ether condenser was used against them.
Jin surmised that whatever mechanism existed at the South Pole likely functioned similarly to an ether condenser. To convert stored mana back into free ether, one would have to use a Magic Canceller, and he doubted such a device would be part of the ancient installation.
"If we equip them with mana tanks like oxygen cylinders, they should be able to operate even at the South Pole."
Jin was about to dive into the technical details immediately when he remembered that today was Vivienne’s birthday party. He stopped himself just in time. Everyone watched him with fond, knowing smiles.
"Anyway, we've covered a lot, but here is the final report. It’s regarding the long-period planet..."
He left the detailed explanation to Laojun.
『The other day, Jack, the magi-brain on the Moon, Uni, launched an unmanned observation probe. It will be making its approach shortly. Once it does, we will obtain much more detailed data.』
"Where is it located right now?" Jin asked.
『Yes, My Lord. The long-period planet will soon reach its closest approach to the fifth planet, Pengolta. Its distance from Ars is approximately six hundred million kilometers.』
"Six hundred million, huh... What about its speed?"
『It is currently slightly less than three hundred kilometers per second. Its velocity will likely increase further as it nears the sun, Celane.』
"That's fast..."
Even with the spaceship Adriana that Jin had built, three hundred kilometers per second was his current limit. Once it reached the vicinity of Celane, it looked like it would exceed four hundred kilometers per second.
『Pengolta appears to be quite a massive planet, so it is likely to influence the trajectory of the long-period planet.』
"That’s the biggest concern."
As of now, they had no way of knowing how an altered trajectory would affect Ars. This wasn't just because Jin was poorly versed in astronomy; it was also because they lacked sufficient data regarding the mass of both the long-period planet and Pengolta. Consequently, even No. 700672 couldn't provide an accurate prediction yet. They simply had to wait for the information from the unmanned probe.
"It seems there is no point in us worrying about it right now..." Toa said, looking a bit disappointed.
"Indeed. It is frustrating to have to rely entirely on Jin-dono," Louis—Earl Kuzuma—muttered with a hint of regret.
"That's not true. It's because everyone is here that I..."
Jin paused. He realized he had said those exact words quite recently. But they were his genuine feelings. A person can work hard for someone else. They can live for someone else. Having those "someones" in your life is a blessing.
The teachings of the Orphanage Director suddenly echoed in Jin's ears.
The Director really was like a parent to me.
"Jin?"
"Oh—ah, sorry."
Jin snapped back to reality at Goose's voice.
"A-anyway, I think we'll know more in a few days. Once we do, things are going to get busy."
Until then, Jin told them, they should focus on keeping their preparations ready.
"Today is Vee's birthday, after all," Stearena said, patting Vivienne on the shoulder.
"Exactly. Let's leave the difficult talk for later and enjoy ourselves for now," Toa added cheerfully.
"You're right."
"I agree."
"Indeed."
Everyone concurred, yet a small thorn of worry remained lodged in the corners of their hearts.
Later, at Hourai Island, after everyone had returned to their respective countries and homes.
Elsa, accompanied by Edgar and Mine, had departed for the Shouro Empire with Reinhard and his wife for a visit to her family home. For the first time in a while, Jin was alone with Reiko.
"Now then, where should I truly begin?"
In the command room, Jin stood with his arms crossed, deep in thought.
"I suppose the emergency mana tanks should come first."
He decided to design them so they would be compatible with all his golems, not just the Mermaids.
"I wonder if I can make it so they can store more mana than the current models."
Since it was an older technology, it was a field that hadn't been fully explored.
"The bottom line is, I need a way to compress the mana..."
"Father, was there any similar technology in the world you came from?"
Reiko offered a rare suggestion. Jin was pleased, seeing it as another sign of her developing ego. Then, it hit him.
"Wait... That's it! A hydrogen storage alloy!"
Though Jin wasn't great at chemistry, he possessed a broad knowledge of metallurgy. Among those concepts was the hydrogen storage alloy.
"If I recall correctly, it was about incorporating hydrogen gas into a crystal structure."
His memory was a bit vague on the exact science, but that didn't matter. The core concept was what was important.
"The mana stored in a mana tank is likely held within the gaps of the crystal structure as well..."
Jin let his thoughts race.
"If that's the case, then rather than a close-packed crystal structure... what’s the opposite of close-packed? Sparse? Well, whatever, I’ll know if I prepare a mana tank with a non-close-packed structure and experiment with it."
Muttering to himself, Jin solidified his general plan.
"Reiko, Laojun, are there any magi-crystals that don't have a close-packed crystal structure?"
『My Lord, I believe that would be difficult. As long as it is a crystal, there should be almost no individual variation in the structure.』
"I thought so."
He hadn't expected much from that line of questioning anyway.
"Hmm, a material other than magi-crystals that could store mana..."
He could think of many materials that stored free ether, but when it came to mana... Jin fell into deep thought.
Generally, mana can only be used by the caster who generated it from free ether. However, exceptionally 'low-level' or 'neutral' mana possesses a degree of versatility. To use a real-world energy analogy, it was like static electricity or direct current. As it is, it's difficult to use, so it must be converted into something else to produce kinetic or thermal energy.
Normally, magic involves converting free ether directly into the desired form of energy. Using a two-stage process starting from mana was inherently inefficient.
However, the children Jin had created—Reiko, the other automata, and the golems—were exceptions. They shared his magic pattern, allowing them to bypass these limitations.
Jin tried to recall a material that could store neutral mana.
"...Ancient Dragon hide, perhaps?"
He remembered from when he modified Reiko that its mana efficiency was incredibly high. That meant it could hold a vast amount of mana and efficiently utilize the energy it produced.
"Let's try thinking along those lines..."
Jin sank into contemplation once again.