After finishing their meal, the group decided to spend the afternoon however they pleased.
Jin wandered aimlessly toward the mine, but once they reached a secluded spot, Reiko deactivated her Stealth and appeared before him.
"Father, it seems something has happened on Hourai Island," she informed him.
"Something? Is it something even Laozi can't handle?"
"No, it sounds more like an important discovery he wishes to report."
"I see. All right, let's head back for a bit."
With that, Jin activated his own Stealth, and the two of them returned to the carriage under its cover. Since Jin was unable to see his surroundings while the spell was active, he had Reiko lead him by the hand.
After ensuring no one was watching, they quietly slipped into the carriage, activated the hidden Warp Gate, and jumped to Hourai Island.
＊ ＊ ＊
"Welcome back, My Lord."
The voice of Laozi greeted Jin as he stepped out of the Warp Gate on Hourai Island.
"Yeah, I'm back. I hear you have a report for me?"
Jin made his way to the room housing Laozi's main unit and took a seat in the provided chair. Reiko stood ready at his side.
"Yes, My Lord. Actually, it concerns the Albatross units."
The Albatross was an aircraft that flew using the Magi Jet Engines Jin had designed.
"We have been continuing the topographical mapping via aerial surveys, but in the process, we have made an unexpected discovery."
"An unexpected discovery?"
"Yes. First, please look at this."
Under Laozi's instruction, a map currently in development was spread out before Jin. The one in charge of the project was the Army golem, Land 1.
"It's well-made."
"Thank you. While the finer details are yet to come, we have a general understanding of the terrain."
"Right. But why is there so little of the southern hemisphere?"
The topographical map depicted the northern hemisphere in great detail, but only a small portion of the southern hemisphere had been rendered.
"That is the core of this report," Laozi began.
"Initially, the surveying progressed smoothly. However, the Albatross units heading south began reporting anomalies. The Sky golems on board reported the same."
"Anomalies?"
"Yes. A decrease in the operational efficiency of the ether converters. However, upon inspecting the returned Albatross units, no malfunctions were found."
A hypothesis sprang to Jin's mind as he listened, but he refrained from jumping to a conclusion due to the lack of data and let Laozi continue.
"Conversely, the Albatross units heading north saw an abnormal increase in the efficiency of their ether converters. The Sky golems on board similarly reported an increase in efficiency."
Hearing that, Jin felt certain his hypothesis was correct.
Laozi concluded that, based on these observations, the concentration of free ether in the atmosphere increases the further north one goes and decreases as one travels south. This matched Jin's own theory.
"Father."
At that moment, Reiko, who had remained silent until then, spoke up.
"In Mother's era, it was said that the north was the land of magical beasts, while the south was the land of humans. I wonder if there is a connection?"
Laozi acknowledged her contribution.
"Reiko, thank you for that valuable insight. My Lord, looking at this information, it seems certain that the free ether concentration becomes denser the further north one goes."
Jin nodded in agreement. Reiko added another observation.
"Moreover, when I was warping to various places searching for Father before, there were regions where the efficiency of my ether converter increased abnormally. Perhaps those were in the north."
Jin voiced his conclusion.
"Yeah, with those facts, regardless of the reason, it seems undeniable. In that case, putting aside heading north for a moment, developing aircraft capable of flying south is an urgent matter."
Working together, Jin and Laozi began designing new aircraft models.
"Let's equip them with three ether converters. We'll also install a large mana tank so they can fly even in areas devoid of free ether."
Unlike mechanical airplanes, ether converters and mana tanks weren't particularly large, so adding them wouldn't significantly increase the size of the airframe.
"My Lord, I also recommend adding more Magi Jet Engines," Laozi suggested.
Jin decided to adopt the idea.
"Alright, let's add one to each wing. With a total of three engines, longer flights should be possible."
While the number of engines and flight distance weren't simply proportional, it would be effective for increasing flight speed and altitude. Jin wasn't particularly well-versed in aerodynamics; his only experience came from building model airplanes. If it didn't work out, he'd simply rebuild them.
They decided to construct several types of airframes.
First was a long-range reconnaissance airframe. It would be equipped with three ether converters and three Magi Jet Engines. With its large mana tank, it could theoretically circle the planet with ease.
Next was a transport airframe. Similar to the long-range recon model, it prioritized payload capacity over flight distance, featuring a larger wing surface area and fuselage volume.
Finally, an airframe for stealth maneuvers. Based on the Albatross, it featured a Stealth function, enhanced attack power, and high-speed movement. It was essentially a stealth fighter.
Jin named them: the reconnaissance model was the Skylark, the transport was the Pelican, and the stealth model was the Raptor.
The names were taken from those he had heard back on Earth. Though one might feel that 'Albatross' was a more suitable name for a long-range reconnaissance plane than 'Skylark,' it was better not to overthink Jin's naming conventions.
＊ ＊ ＊
Once the general designs were finished, Jin took another look at the map.
Through the surveying done so far, they had a general grasp of the planet's size.
"But it's smaller than I expected."
The diameter of the planet calculated by Laozi was approximately 2,400 kilometers. Compared to Earth's diameter of about 12,700 kilometers, it was quite small.
"As I thought, it must be packed with heavy elements... likely magi-elements."
Jin was curious about the planet's structure as well, but he pushed those thoughts aside for later.
"Laozi, there seems to be an unsettling atmosphere in this world as well. Do not lower your guard."
"Yes, you mean the Master-Slave Rewrite Magic and the Unifilar. I have received reports from Reiko as well."
"Yeah. If they find out about this place, they'll definitely target it. Be careful."
"Understood, My Lord. In that case, Kaina Village also requires vigilance."
"True."
The name of a village special to Jin. A village that could be called his second home.
Jin felt a swelling of hope that now, as an Honorary Magi Craftman of the Kingdom of Egerea, he might be able to visit the Klein Kingdom and Kaina Village openly. However, it seemed that would still be a little ways off.
Afterward, Jin spent time listening to detailed reports on the island's development and the situation on Kunlun Island.
In short, everything was progressing very smoothly.
Finally, he asked about the mining of Elradrite, but unfortunately, no veins had been found on either Hourai Island or Kunlun Island.
"Well, it can't be helped. Continue the search."
"Yes, My Lord."
With that, Jin stepped back through the Warp Gate and returned to Yada Village.
＊ ＊ ＊
Yada Village was still bright due to the time difference.
Exiting the carriage, Jin took the opportunity to check for any damage or issues, but found no abnormalities.
"Ah, Jin-kun."
A voice called out to him. He turned to find Elsa.
"What are you doing?"
"Just checking the carriage. We're heading to the village with the ruins in this tomorrow, right? So I figured I'd give it a look."
Elsa nodded, looking impressed.
"Jin-kun is admirable. Even after making something this incredible, you're still so careful."
"Haha, flattery won't get you anything."
Jin replied to Elsa's praise with a grin, then clapped his hands together.
"All right, no problems here."
"Mm."
"I hope the weather is good tomorrow."
Jin looked up at the sky as they walked side by side.
The sunset-tinted clouds seemed to herald clear skies for the following day.