The Fifth and Sixth Tier-Groups

Adachi is a barren wasteland made up of lowlands and low plateaus around 10 m high. The library dungeon stands atop a hill some 100 m high and about 2 km across, perched on a plateau that runs from northwest to southeast. Six tier-groups, 44 floors; including the hill, about 300 m tall.

If this world were flat, or a sphere the size of Earth or larger, then in theory one could see all the way from the rooftop to the Iruma Magistracy in Kasumigaseki, about 60 km to the west, but between that and the limits of the surveillance cameras, in reality you can't see anywhere near that far. (Of course, the metric system does not exist in this region.)

[Core Room]

"Marie-san, what on earth was it that let us add two whole tier-groups at once, I wonder?"

"I'm not entirely sure, but it seems there are certain benchmarks, like the 'number of adventurers staying in the dungeon at the same time' passing 100 and then 1,000, or things tied to the adventurers' abilities, health included. It's only a one-time windfall of dungeon energy, though, not something we'll keep receiving."

"Next is 10,000?"

"Probably. Then again, it may be that a staying population of 10,000 was never even anticipated. A human farm is one thing, but it seems unlikely an ordinary dungeon would ever have 10,000 people in it at once."

The sixth tier-group is the central library of a certain special city in western Japan, a large building 90 m east-west, 70 m north-south, six floors above ground and six below, with a total floor area of 34,000 m². Below it, sitting atop the existing fourth tier-group, the fifth tier-group is the prefectural library of a neighboring prefecture located, in the otherworld, 10 km east of the sixth tier-group, 90 m east-west, 90 m north-south, four floors above ground and two below, 30,000 m² of total floor area, and, like the fourth tier-group, shaped with the southeast corner cut away.

"I have nothing but gratitude for Mint-san, Sapien-sensei, and Miss Maid, who are moving the settlers' education along. I'd like to add more hands, but there's a limit to what nameless monsters can do, and if I increase the named ones I won't be able to look after them all."

"In your case, Master, it's that you can't keep all the names straight. Isn't it."

"That too."

"Which is where a hierarchical organization comes in. The proper number of subordinates is said to be four to six. And once a meeting has more than seven participants, productivity is said to drop. So we educate a portion of the settlers and assign them under each Shiso. The technical level in this region is on par with the Edo period, but that doesn't mean the individuals are inferior, and with a thousand people there are bound to be a few with real ability."

In this world you can't see things like a status screen; before that, you couldn't even put them into numbers. If I were forced to make a rough, sweeping appraisal anyway, it would be:

Marie: Knowledge AA, Intelligence A, Senses D, Dexterity B, Agility C, Strength D, Endurance A, Willpower AA, Magic ×, Health AA, Luck AA, Chest AAA. Something like that… pretty high stats, Marie. And some off-the-chart entries.

※ Ratings basically run A to E. AA means "exceptionally outstanding," AAA "off the charts," F (Failure) "Yōzō Ōba (No Longer Human)," G "beyond discussion."

"Even so, most of the residents can't so much as read or write. This world may be on par with the Edo period, but for that the literacy rate is far too low."

"On par with the Edo period, you say, but while literacy in Edo itself was extremely high, out in the countryside it was around half. Gather up nothing but landless farmers and people with no work, and that's how it ends up."

"Marie-san, about future summons: first, a soldier is essential. Next, in time we'll need a mayor too. And I want an agriculture specialist. Setting aside whether I can remember the names, is there an upper limit to how many dungeon monsters can be summoned?"

"There doesn't seem to be any particular limit, but in this dungeon's case the first two named ones are a given, and beyond that the cap is the number of tier-groups, plus one. There may be unique laws out there that raise the cap, but still."

"We have up to a sixth tier-group, so that's seven, then."

"No. The first and second tier-groups are relatively small compared to the dungeon as a whole, so they're lumped together as a remainder, making it six. Two more, then. You can't, say, build a huge number of tiny tier-groups, ones with literally a single room each, and organize a great horde of named monsters that way."

"If we're building an army, that's a nuisance."

"At the very least the noncommissioned officers have to be named, or you can't wage war. And for an expeditionary force, every last soldier has to be named, or they can't even leave the dungeon."

"So what we'd really need is a colossal dungeon of thousands of tier-groups. Is it."

"Master, as the number of tier-groups grows, each individual tier-group's share of the whole shrinks, so beyond a point they get treated like the small tier-groups, and the number of named ones doesn't increase much. In other words, it's difficult to organize a proper military unit out of dungeon monsters.

"If a dungeon without some special unique law were to conquer another dungeon, it would have to either prepare monsters overwhelmingly powerful even without a unique law, or make only the commanders named monsters and tame wild, non-dungeon-bred beasts for the rest, or hire adventurers or mercenaries, or use some groundbreaking method I haven't thought of. One of those."

"Supposing we did set out to conquer one, which dungeon is nearest from here?"

"From what the adventurers say, the Nakayama Racecourse dungeon is about ten days to the southeast, though whether it's still alive is unknown. But it's in another country, so there's little contact, and even the town of Kōnodai short of it, the magistracy of Katsushika in the province of Sō, has not a single village before you reach it, so it's camping the whole way. There are surely others as well."

"Ones the adventurers don't even know about?"

"Either no one knows, or, since adventurers have no guild the way merchants do, it's simply that the adventurers who frequent this place don't happen to know."