How to Make Use of Dungeon Structures

[Core Room]

"Marie-san, a dungeon structure crumbles when you 'release' it, doesn't it."

"Yes. That is how the traps work. For a pit trap, we strip the ceiling out of the dungeon structure and let it collapse."

"If you 'release' a sheet of glass, does it shatter into powder? Or does it keep its shape, being glass?"

"It is made from sand, so most likely it would revert to the desert sand it came from."

"Then, say, if we made an iron plate out of scrap iron like empty cans, would it turn back into the cans?"

"Most likely not. By the irreversibility of entropy, it would not return to cans but become iron powder instead… Shall we test it?"

[Tier-Group 3, Plaza Before the Entrance]

"Gather up the unwanted ironware, then. Now, with the dungeon's power."

The iron parts squirmed together like slime and gathered into a single small iron plate. The things that weren't iron, meanwhile, were left lying about where they were.

"It's magic, no matter how many times I see it."

"It is the dungeon's power. 'Magic,' too, is most likely the same thing at bottom."

"And now this iron plate is a dungeon structure."

"Yes. I shall try releasing it."

Nothing happened.

"Hm. It isn't releasing."

"So it's still a dungeon structure."

"… It should not be a dungeon structure anymore… Could it be that sand simply crumbles apart, while an iron plate keeps its shape even once released? A dungeon structure cannot be easily broken, so if we can drill it or machine it, then it is just an ordinary iron plate."

[Core Room]

"So, to sum up."

"A dungeon structure can only be made of simple compositions, but we can exploit that 'simple composition' to refine things. We take a material that contains impurities, make something out of it once as a dungeon structure, then release it. As just now, we can refine iron from scrap iron, for instance. That said, in terms of energy it is more efficient to run an electric furnace on the power the Core supplies."

"An electric furnace, that's a steelworks. If we don't need anything that grandiose, isn't this extremely useful at our current stage?"

"It also solves the dungeon structure's problem of large dimensional error: we machine a part with a machine tool first, then designate it as a dungeon structure. In other words, we can easily produce parts of extremely high strength. Outside the dungeon, of course, they revert to ordinary objects."

"They are absurdly strong, after all."

"That said, while this dungeon's main body is strong enough that it wouldn't be crushed even with a tower some 20 km tall stacked on top of it, parts other than the main body don't seem to have anywhere near that strength. With a very small iron plate, applying force snapped it clean off rather than bending it. So a certain amount of strength calculation will be necessary."

"And the fact that refining is possible means we could gather up vast amounts of desert sand and extract gold, doesn't it."

"In theory, yes. Though it would take an absurd amount of dungeon energy."

"Would it take sacrifices by the tens of thousands?"

"Well, surely there's no one left who would seriously come to attack this dungeon anymore."

"In that case, it's only as much as the residents who pass away from old age and the like."

"We had best think of something. According to a book called the Description of Formosa, in Japan they offered great numbers of sacrifices to Amida. Could that be a book that drifted in from a world that has dungeons, I wonder?"

It is a work by the Taiwanese Psalmanazar, published in England during the Edo period; but in the otherworld closely tied to the Library-City Dungeon, it is regarded as a "forgery."