"Only half... you say?"
"Precisely. Amplifying magic is merely a secondary effect. Its original purpose is 'compression'."
"Compression?"
"Indeed. Compared to a normal magi-crystal, it can achieve a compression ratio over a hundred times higher."
Jin considered the implications. It was likely that Elradrite functioned by drawing in the user's mana, storing it temporarily, and then converting it into magic.
The process of temporary storage occurred in an instant, so one wouldn't feel any time lag.
If this could also be done with free ether, and it could be compressed indefinitely without being released, then that would mean...
"Matter creation?"
"Exactly. I am impressed you reached that conclusion. Yes, it appears my master believed that by using this Mityanite, it might be possible to create new elements."
"He believed?"
"Regrettably, he did not succeed."
Even the Origin, with his exceptional knowledge and skill, had been unable to achieve it.
"What happens if you keep pouring in free ether and compressing it inside? The result is... collapse. The Mityanite shatters."
"I see..."
Jin looked disappointed.
Using a different approach, Jin had managed to synthesize light elements like hydrogen and helium from free ether, but synthesizing heavier elements remained out of his reach.
"Now, wait. I am not finished. It was during that research that the idea of using it for authentication was born, focusing on its ability to 'store magic'."
"Eh?"
When Jin had analyzed the Celuroa Kingdom's Key-Seal the other day, he had suspected it possessed such a function, but his investigation at the time had not reached a final conclusion.
Specifically, he hadn't been able to explain how the Key-Seal allowed specific individuals to Wake up targeted magic tools or Magi Machines.
Jin had moved on from the analysis after leaving the Celuroa Kingdom, so he didn't know if there had been any subsequent progress, but he suspected the mystery remained unsolved.
"Authentication...?"
Jin was about to ask what that had to do with the ability to store mana or magic when he suddenly realized the truth.
"...This isn't just a 'key' for authentication; it's the authentication unit itself, isn't it?"
No. 700672 beamed upon hearing that.
"Precisely. As expected. To reach the correct answer with only a few hints—your insight is remarkable. Could you explain the principle as you see it?"
"Yes. The necessary information is recorded into this Mityanite. Then, by comparing that internal record with external input, its function as a key activates once the conditions are met."
"Mhm, that is roughly it."
"I knew it."
Jin realized that, in that case, the Celuroa Kingdom's Key-Seal also chose its own owner.
Even if Orange had tried to use the Key-Seal, it likely wouldn't have worked for him.
"The magic possessed by a magi has parts that clearly express their unique characteristics. As far as we know, it has three characteristic peaks..."
No. 700672 explained that these were traits manifested within the same bloodline, similar to fingerprints or voiceprints.
Jin wondered if perhaps the giant golem artifact of the Shouro Empire also detected those kinds of waveforms.
(Wait... what about my method?)
Jin's method was literally to "overlay" the waveforms and give the OK if they matched by more than 90 percent.
In effect, any mana waveform other than Jin's would be rejected.
(Though, there's no real benefit to making it more simplified...)
Jin and the golems and Automata he created possessed the exact same mana waveform as Jin himself.
Furthermore, since the number of people in the Jin Family was limited, there didn't seem to be any particular problem with his current method.
And there was one more thing.
Since Jin did not own any Elradrite (excluding what he had obtained during the battle with the Unifilar), the mediums he used to Write In waveforms were magi-crystals.
This required the manual effort of a "Write In," which couldn't be done unless one was a practitioner of Craft Magic.
In that regard, the advantage of Mityanite was that it could be used simply by flowing magic through it.
(I see. In the case of the Key-Seal, if the owner changes, it's possible to overwrite the data again.)
Thanks to No. 700672's explanation, all the mysteries Jin had concerning the Celuroa Kingdom's Key-Seal were resolved.
No. 700672 continued.
"...In short, this Crystal Cube is proof of who my master is."
"Which means..."
"Yes. It can prove a connection to those who serve the same masters—the Origin."
No. 700672's gesture was an act of kindness, intended to ensure that if Jin took this with him, he wouldn't be met with hostility.
"Thank you very much. I will borrow it."
Jin expressed his thanks and accepted the Crystal Cube.
He peered closely at the object.
"Still, Mityanite... it's a mysterious stone."
"Mhm. This mineral did not originally exist here on Ars. It is what one might call a meteorite."
"A meteorite...?"
A surprising fact was revealed.
"It seems to have fallen in the distant past. That is why its production areas are so limited."
"I see..."
If that was the case, Jin thought, it made sense why the sources were so extremely restricted.
＊ ＊ ＊
After returning to Hourai Island, Jin sat down to think about his future plans.
It was noon. Elsa had also returned and had prepared lunch.
Today's meal was zaru soba. It was served with nori farmed in Tatsumi Bay and some "mock spicy daikon" that they had only recently begun to cultivate. Since the cultivated crop wasn't ready yet, this was a wild variety.
"Yeah, the boiling time is just right."
Slurping the noodles, Jin praised Elsa's cooking.
"Mhm. I finally have a feel for it."
Boiling soba was difficult. If one was even slightly careless, it would immediately become mushy.
At a certain soba shop, they apparently said, "We don't serve large portions; if you want to eat a lot, please order fresh ones each time." The reason was said to be that "the soba stretches and loses its flavor even while you're eating it."
Digression aside.
After finishing with some soba-yu, Jin and Elsa spent some time relaxing over buckwheat tea.
Elsa talked about the smoked river fish she had made with Hanna, and Jin shared what he had learned from No. 700672 regarding Elradrite.
"...I see. It sounds like you had a good time."
"Mhm, it was fun. It seems you heard many useful things on your end, too."
And then, in a natural flow, the conversation shifted to their next move.
"I really think we should take Belialus along, too."
"Mhm, I agree. Even if we can manage that servant-like opponent with the Crystal Cube you received, I think persuading Arshel will be difficult."
"Right."
"So, I agree with taking Belialus-san along."
Elsa was in full agreement regarding bringing Belialus of the Puppet Clan.
"But, Jin-nii, you must not go."
"Hey."
"...It is dangerous. No."
"My Lord, it is exactly as Elsa-san says. The opponent seems to have obtained a certain amount of information about you, My Lord, so we must not be careless."
"I agree with Laojun. I believe it would be best if you did not go this time, Father."
"Just like when you went to the demon territory."
They were telling him to use his Body Double.
"...Alright, I get it."
Persuaded by Laojun, Reiko, and Elsa, Jin finally gave in.
"My Lord, I would also like you to consider the matter of Fort Crow."
With that, Laojun began to explain the current situation at Fort Crow, where Lufort de Orange had fled.