Jin began explaining to Saki what he speculated to be the causes behind the resource depletion on Planet Hehl.
"First of all, the vast majority of the Origin Clan practiced 'space burials.'"
"Space burials?"
"Yeah. In other words, they placed the deceased aboard spaceships and sent them off toward the Sun."
"Ah, I see."
In that case, the materials used for the spaceships and coffins could never be recovered. They were inevitably consumed and lost forever.
"Hardly any grave sites remain on this Planet Hehl, after all."
"True. If they kept that up for thousands of years, the resources might really dry up."
"On top of that..."
Jin moved on to explain the next possibility.
"Even before the resources were depleted, the Origin Clan launched numerous space probes for cosmic exploration."
"Ah, and most of those never returned either, right?"
"That's right."
Continuing that for thousands of years would undoubtedly consume a vast amount of resources as well.
"Still..." Jin added. "Honestly, it feels strange that just that alone would cause total depletion."
"Meaning?"
"Unless there was another decisive issue of some kind, I can't quite accept that resources were drained to this extent."
However, there were no records concerning this, and No. 700672 did not know either.
"Is that so..."
"So, from here on, it's complete speculation—or rather, a hypothesis that could practically be considered fiction. Do you still want to hear it?"
"Since you've told me this much, I'd love to."
"All right."
Jin nodded and began sharing his theory.
"First, although it's not recorded, perhaps a portion of the Origin Clan boarded spaceships and departed for somewhere far away. To set off for a distant destination that would take generations to reach, I imagine they would have taken a considerable amount of resources with them."
"I see. That's... plausible, maybe?"
Saki nodded in acknowledgment as well.
"Second. A hypothesis that the Origin Clan made use of technology to convert matter into energy to do something."
In addition to the energy obtained from free ether, converting matter directly into energy would yield an immense amount of power.
"I discussed it a bit with Laojun, and he mentioned the possibility that they might have conducted experiments to transcend time. Though it's strictly a possibility, of course."
The energy Laojun had consumed to send Jin's main body four hundred years into the past had been tremendous.
Most of it had been energy derived from free ether accumulated over the span of four hundred years, but if converting matter into energy had been used alongside it, the process might have been a little easier.
"Aha. It wouldn't be surprising if the Origin Clan were conducting that kind of research."
Saki agreed that this, too, seemed likely.
"Third. There's no evidence for this, and it's quite absurd, but someone might have snatched the resources away."
Jin chuckled, admitting that this bordered on pure fantasy.
"Hmm, well, in any case, it's a fact that resources are scarce on Planet Hehl, and I understand that there's no way to verify it."
Having heard Jin's explanations, Saki seemed satisfied for the time being.
"Anyway, that's enough of that. I think I'll start researching the new material."
It was a material with an "abnormally high affinity with free ether."
"I heard you initially named them 'ether silver' and 'ether copper,' Jin."
Saki remarked with a slightly exasperated air.
"Give me a break, I put 'Neo' in front of them now."
"Kufu, fair enough....Is there anything we already know about it?"
"Yeah, only that it's stable."
Jin explained that, assuming one of the reasons for its formation was its presence in an area of high-concentration free ether, there was a possibility it might gradually revert to an ordinary material if stored in normal concentrations, but that hadn't happened.
"Beyond that, we've barely started."
"Kufu, that makes it all the more worthwhile!"
Saki showed her enthusiasm by making a show of rolling up her short sleeves even further.
"Oh, come to think of it, Laojun speculated that instead of the ore becoming like that simply by being located in a high-concentration free ether area, it might have been in that area before even becoming ore... while it was still in the state of magma."
Remembering one more detail, Jin shared it with Saki.
"Oh, what an interesting hypothesis. Thanks, Jin."
Jin then asked Saki, "Hey, what happened to the research on the 'Gigant Peeder carapace' you were doing until recently?"
"It's reached a temporary stopping point for now. Laojun should be putting the report together."
"Talking about free ether reminded me—we used that material for 'mana tanks' before, right?"
Jin brought up the thought that had popped into his head. To that, Saki replied with a question of her own:
"Ah, we did. But how much do you think that actually uses?"
"Uh..."
Assuming they were made roughly the size of an AA battery, each one would be roughly seven cubic centimeters.
The carapace of a 50-meter-class Gigant Peeder was 20 centimeters at its thickest parts and 5 centimeters at its thinnest. On average, 10 centimeters.
Approximating this as a cylinder 50 meters long and 5 meters in diameter yielded roughly 38 million cubic centimeters.
Factoring in material loss, approximately 5 million mana tanks could be produced from a single creature.
Even if 50 were prepared per unit, that was enough for 100,000 units...
Even combining all the golems and automata on Hourai Island, there weren't even 10,000 units. Even if all of them were equipped, over ninety percent of the material would be left over.
"I get it. There'd be plenty left over even after equipping everyone, so you were thinking about other uses for it."
"Exactly."
After Saki jogged off toward the laboratory to research the new material, Elsa came over.
"Would you like a refill on your tea?"
"Yeah, I'll take one."
His throat parched from all the talking, Jin received a refill of barley tea and took a sip.
"Is your research making progress, Elsa?"
"Mm."
However, Elsa said there were many difficult issues.
"When dealing with plants, research has to be done thoroughly and carefully."
In that regard, she mentioned that becoming a homunculus meant she no longer had to worry about time.
"For example?"
"Magi-craft works on severed branches right away, but severed branches shouldn't be dead yet. Like the reason for that."
"Ah, I see."
"Cuttings"—the technique of taking cut branches and planting them in soil to propagate them. This was only possible because the branch remained alive even after being cut, so why did magi-craft take effect immediately once it was severed?
"What I talked about with Jin-nii a little while ago might be the correct answer."
"Hmm, that really is a difficult question."
"Mm. But thinking through it is fun. Because I have plenty of time."
"That's true....If you ever get stuck, you can always consult me."
"Thank you."
Thus, Elsa too appeared to be diligently devoting herself to her research.