Upon returning to Hourai Island, Jin immediately gave a detailed report to Elsa and Saki.
"The shed skin of an Ancient Dragon!?" Saki practically pounced on the information. "Jin, you're going to look for it, aren't you? You have to go!"
"Y-Yeah," Jin replied, feeling a bit overwhelmed by her intensity. "But we need to prepare. The real problem is the Frost Dragons."
"That's right. Based on what we know, they likely unleash magic close to Absolute Zero."
Jin's analysis seemed sound, and Elsa nodded in agreement. "In that case, we need proper countermeasures."
"Father, are the weapons we have developed thus far insufficient?" Reiko asked, looking puzzled.
"No, it's not that. I just want the appropriate tool for the job. If it were a single opponent, a laser or a magi-cannon would be fine, but their power is too high. Frost Dragons are rare, and I don't want to disrupt the ecosystem unnecessarily."
"Heh, I see. That is a very 'Jin' way of thinking," Saki said with a smile. "So, to counter the cold, does that mean you'll be using fire-attribute magic?"
However, Jin shook his head. "No, that would be too inefficient. Instead of trying to counter it directly, I think it is better to use an attribute that isn't easily affected by it."
"...I understand. So, lightning or light?" Elsa asked.
"Let's see..."
Reiko spoke up then. "Father, if you only intend to drive them away, wouldn't the transporter gun be sufficient?"
The transporter gun operated on the same principle as a transporter, sending the target far away. It fired waves of mana rather than physical projectiles. Due to its nature, the destination was fixed, and because of the high energy consumption, it was usually a single-shot weapon—or at most, it could fire twice.
"That's a good point. I can modify the transporter gun, using a cartridge system for the mana to improve its usability. Then I'll just expand the effective range to handle a giant dragon."
"Mm, I think that is a good idea."
"It's non-lethal, so I'm all for it too," Saki added.
With the plan decided, Jin immediately moved to his workshop on the first floor to begin the modifications.
"I'll start by standardizing the shape of the mana tanks. Once they're empty, they can be swapped out and recharged for reuse."
He had the image of a AAA rechargeable battery in mind.
"...It is better to standardize things like this for the future."
Following Elsa's advice, Jin decided to think about long-term compatibility rather than just building on a whim.
Thinking about it that way, dry-cell batteries were actually a pretty clever invention, Jin thought. Except for button cells. Those were always a nightmare to keep track of...
He decided to create a "Type I" tank, roughly the size of a AAA battery, to serve as the future standard. He would worry about Type II and beyond when the need arose.
"I think this is a good path," Elsa agreed.
Jin began shaping magi-crystals into cylinders and engraving the magi-formula onto them.
"...Wait, what are you doing?"
This time, Jin was engraving the magi-formula inside the magi-crystal itself. It was the same concept as 3D laser engraving inside crystal glass. While he couldn't achieve the same level of extreme precision as surface engraving, it was more than enough for a mana tank.
"Hm? This way, the magi-formula won't wear off or get damaged from friction, right?"
"...I understand the logic. But the fact that you can actually execute it is what is truly amazing."
"Truly. It really hits home that Jin is the Magi Craft Meister," Saki said, clearly impressed by the technical feat.
After producing about twenty of these cartridge-style mana tanks, Jin moved on to the transporter gun itself.
"I wonder if I should add a few more functions while I'm at it."
Elsa offered a word of caution to the easily distracted Jin. "But I think it would be bad if it couldn't be used as a transporter gun in an emergency."
It was a choice between specialized ease of use and general-purpose convenience.
"I see... In that case..." Jin proposed making the weapon function as a transporter gun by default, but allowing it to switch to a Paralyzer or a laser gun through specific operations. "I'll set it up so that it requires a deliberate sequence to change settings. That way, we don't accidentally fire the wrong thing."
"Mm, if it's like that, then it should be fine."
"Right, let's go with that."
Jin began the actual fabrication. Elsa watched intently, eager to learn his techniques. Saki looked on with an appreciative air, simply admiring his dexterity. Reiko prepared the necessary materials and double-checked the overall process to ensure nothing was missed.
An hour later, five new-model transporter guns were complete. Their design bore a subtle resemblance to a Luger P08. The cartridges were swapped by opening a lid at the base of the grip, much like changing a battery, rather than using traditional shell casings.
"You hold this button while turning the dial at the rear. Position 1 is the transporter gun, 2 is the Paralyzer, and 3 is the laser gun."
The dial wouldn't turn unless the button was depressed, acting as a safety. Additionally, the dial would glow red when set to the lethal laser mode to prevent any accidental usage.
"There is one more safety device," Jin said, pointing to a small magi-crystal near the muzzle. "If you record a magic pattern in here, the gun will refuse to fire if pointed at that person."
"That is excellent," Elsa praised. It meant there was no risk of accidentally hitting a member of the Family. Since Laojun had records of everyone's magic patterns, Jin simply copied the data over.
"There, all finished."
The guns were crafted from 64 light silver, making them light and durable. He had finished the surface in a vibrant red. While he chose the color as a warning of the weapon's danger, it would also make them easy to find in the snow and ice of the north.
Jin, Reiko, Elsa, and Saki each took one, leaving the fifth as a spare.
"Heh, it feels a bit intimidating," Saki said with a slightly troubled look as she held the weapon. She had lived a life far removed from such tools of conflict.
"It's just for this expedition. I'd like to live in a world where we don't need things like this," Jin replied.
He considered giving the spare to Saki's personal automata, Aaru, but she was slightly lacking in basic performance specifications and wouldn't be joining them on this trip.
"I see... I'll need to reconsider the Secret Mobile Unit as well..."
Lately, Jin traveled almost exclusively by airship, which meant the Secret Mobile Unit had a hard time keeping up.
"I'll either have to improve their flight capabilities or assign them to different roles."
If it was just for protection, they didn't necessarily need to be human-sized; mini-sized golems could serve the purpose. They could hide in pockets or luggage and provide an escort.
"Well, I'll think about that when we get back."
More importantly, Jin had one more decision to make: the means of travel.
"I think the Konron 2 might find the Arctic Circle a bit too demanding."
He anticipated extreme cold and fierce gales. The cold could be managed, but high winds were a serious problem for an airship.
"It's a shame, but maybe we should take Pegasus 1...?"
"Father, wouldn't it be difficult to spot the Ancient Dragon's shed skin from the air?" Reiko pointed out.
"Ugh, you're right."
Searching for a specific object on a snow-covered plateau definitely required a ground vehicle.
"...Should we use Capricorn 1?"
It was the four-legged walker he had built for his trip to the demon territory. However, its current capabilities seemed insufficient for these conditions. Jin glanced at Elsa.
"...Permission granted," Elsa said, nodding with a smile as she realized what he was thinking.
"Alright, it's time for a renovation!"
To ensure they could traverse the land of extreme cold, Jin set to work on upgrading Capricorn 1.