"Hey, Jin-nii."
"Hmm?"
"I don't think that counts as fair compensation."
"Ah."
Jin realized she was right; he wasn't actually the one who needed the magi-communicator technology.
"Hmm... but if I accept it as a reward and then use my position to spread it..."
"Then I suppose it's... fine?"
Jin had figured it was acceptable as long as he wasn't seeking personal profit, but Elsa’s blunt assessment made him pause and reconsider.
"Well..."
"I’m sorry. I shouldn't have nitpicked."
"No, it's a good point."
He reflected on his momentary lack of oversight. Seeing the two of them like that, Clan Chief Fabius stepped in to offer a solution.
"We have recently begun mining ore as part of the cave's redevelopment, and we have been finding this. It appears there are significant deposits."
Fabius pointed toward a container.
"This is..."
"...Mercury?"
"No. It’s magi-mercury."
A magi-isotope of mercury. Jin had suspected it must exist somewhere, and now he had proof that it was produced within the demon territory.
I remember someone mentioning it being on a southern island, so there must be other sources too, he thought, his eyes glued to the substance.
"...Jin-nii, this magi-mercury is different from what I expected."
"Eh?"
Elsa had used Analyze on the liquid metal before him and was already ready to report her findings.
"It isn't emitting any mercury vapor."
"What?...Analyze. I see..."
Jin fell into deep thought. He remembered an incident in the Celuroa Kingdom involving a Golem that utilized a Fluid Form Drive. The liquid metal used in that machine—likely a different magi-isotope of mercury—had released vapors that severely damaged the user's brain.
However, the substance before him was different.
"Hmm... For some reason, while its melting point is the same as regular mercury, its boiling point is much higher."
"Yes, I think so too."
"Is it because of the magi-particles, or perhaps the effect of the free ether...?"
In any case, the fact that it seemed far less toxic to the human body was excellent news.
"This is wonderful," Jin replied.
"I am glad to hear that."
Fabius looked visibly relieved.
With that, they decided that magi-mercury would serve as the compensation for the technology.
"What should we set as the unit price?"
"I will leave that to your discretion, Jin-sama."
"Well, even if you say that..."
When it came to the market price for raw metallic materials, Jin was a complete amateur. Ultimately, after consulting with Laojun, he decided to treat it as a precious material equivalent to adamantite. That meant ten million Toll per kilogram—equivalent to a hundred million Japanese yen.
However, when he proposed this to Fabius, the chief protested.
"That is absurd! A tenth of that would be more than enough!"
In the end, they settled on one million Toll per kilogram.
Fabius stared in disbelief as Maquina effortlessly hoisted the container, which held over a hundred kilograms of the heavy liquid metal.
"Saki will probably be delighted."
"Mhm."
Jin intended to entrust Saki with the research of this new magi-mercury.
After staying overnight in the Gospel clan territory, Jin and his party proceeded to visit the other clan settlements one by one.
The Puppet Clan, the Erosion Clan, the Loftiness Clan...
Every clan was overjoyed to receive the Golem horses and agreed to Jin's diplomatic proposals.
"The fact that the demon race is organized into these distinct clans... perhaps it's a trait inherited from their individualistic Halean ancestors," Jin mused to himself aboard the Vulcan during their transit.
"That may very well be the case, Father," Reiko responded, having overheard him.
Jin found himself thinking that this might be where their ancient bloodline showed itself most clearly.
"Still, I didn't expect to acquire this much magi-mercury."
Perhaps because they now had more resources and labor to spare, the other clans had also begun mining, and Jin obtained an average of a hundred kilograms from each. By the time they were finished, he had nearly a ton of the material.
Given its high specific gravity of roughly 13.5, the actual volume was only enough to fill a single large barrel.
"Hmm. Does the magi-mercury found in the northern lands have a higher free ether content?"
The magi-mercury that was reportedly found in the south, where free ether was scarce, apparently displayed physical properties almost identical to regular mercury.
"Jin-nii, that's certainly possible."
"I thought so. Since the strength of ground spider silk varies depending on where it's produced, it makes sense that minerals would be affected, too."
"I believe your hypothesis is correct, Master," Anne agreed.
"Then it really must be related to the free ether concentration."
The realization made Jin want to get his hands on a sample from the southern source for a direct comparison.
"Whoa! Jin, this is incredible!!"
As expected, Saki was ecstatic.
"Saki, it looks safe, but mercury is still mercury. Handle it with caution, alright?"
It would be a tragedy if she suffered mercury poisoning.
"I know, I know. I'll have Aaru handle the physical manipulation of the material."
"That's for the best. Also, make sure the lab is well-ventilated. And don't forget your mask."
If she intended to conduct experiments to find the boiling point, she needed to be extremely careful not to inhale any fumes.
"I'd honestly feel safer if you wore a simplified spacesuit."
"Mmm, I'll do my best."
Saki flashed a grin at the worried Jin and Elsa.
"Laojun, keep a close watch on her."
Still feeling uneasy, Jin gave Laojun a final, firm instruction.
『Yes, My Lord. I have noted your concerns.』
"I'm counting on you."
Only then did Jin finally feel somewhat at ease. Saki had been complaining that he was being overprotective, but for Jin, who knew how reckless she could be when focused on research, he couldn't rest otherwise.
"Now then, next we'll head to Mitsuho."
Jin’s busy schedule showed no signs of slowing down.