The Third Tier-Group

(An introduction to the newly established Tier-Group 3.)

Tier-Group 3 is a university library, eleven stories above ground and four below, with a total floor area of 37,000 square meters.

In a library dungeon, basement stacks don't vanish into subspace, so the basement levels are likewise stacked straight on top of the existing tier-groups (groups). Because Tier-Group 3 has a considerably larger footprint than the existing library, it's supported in midair by pillars of dungeon structure. Furthermore, the part eleven stories up from ground level is the first floor of Tier-Group 3, so the plaza in front of the library spreads out in midair. It's awfully unbalanced and unsightly, so eventually we'd like to summon small-to-medium residential zones underneath to fill it in. Since only libraries can be summoned, that means summoning some suitable library and converting it into housing, but still.

Of course, since an inter-tier-group (group) elevator common to medium and large dungeons was installed running from ground level to the upper floors, movement is easy. This is not a facility unique to library dungeons; it's generally called a "transfer circle" and the like, but physically it's nothing more than an elevator.

[Tier-Group 3, Basement Level 3]

Tier-Group 3's Basement Level 3 works out to the eighth floor counting from the ground, but it was originally a basement book stack, with empty bookshelves lined up across the whole floor.

"Marie-san, there are no books here."

"The collection will be summoned separately, but this library's holdings, including those squirreled away in branch libraries or privatized in research labs, can all be summoned."

"Sounds like it'll grow quite a bit."

"Tier-Groups 1 and 2 are ordinary regional public libraries, so their holdings of specialist books were thin."

Of course, since it's replication summoning, no university library somewhere in some world vanishes, nor do its holdings go missing.

"Still, to fill every one of these shelves…"

"It can house five hundred thousand volumes. There's one more floor of basement stacks, so call it a million volumes. The open-shelf stacks on the upper floors will be converted to residential zones, so we won't count those."

"Even reading ten books a day, that's close to three hundred years."

"Since it's a library dungeon, it's possible to read faster by expending dungeon energy, but I can't very well spend all my time reading books. Eventually I'm considering summoning the Imperial Library (i.e. the National Diet Library) and summoning its entire collection of tens of millions of items, too."

A university library with a collection on the order of ten million volumes has a large staff, so even with a NEET librarian or two mixed in who do no work and read books all day long, it'd run without trouble. But a library dungeon with only three people can't afford such luxury.

"And that's the final goal?"

"For now, yes. Also, the Imperial Library, the Library of Congress, the British Library, and the National Library of China each fit roughly within 150 meters square per building, so I'll secure a ground-level area of about 200 meters square to allow a little margin."

"Wait, you intend to summon all of them?"

"It's purely a matter of allowing for the possibility, just in case. In the case of a cave or a tower, maintaining the dungeon itself doesn't require all that much energy, but this library dungeon substitutes the World Core's energy for electricity, so the upkeep inevitably comes pricey."

"Do ordinary dungeons have energy to spare?"

"According to the 'Encyclopedia Dungeonica,' creating a forest in a large underground space and lighting it up, or installing hot springs and other volcanic-zone features, immediately strains the energy. Those aren't electricity, of course, but I don't know by what principle they work.

Normally, though, the energy goes toward moving large numbers of monsters. With Named ones it becomes indirect, since it's the summoning of food."

"This dungeon has only three monsters."

"We can make the Core Room 'No Unauthorized Entry' by unique law, so we don't need monsters for defense, and our products are books and newspaper, so we don't need monsters for drop items either."

"Or rather, because we can't summon any."

"Ox-Head and Horse-Head, a Minowakka for instance, would make for fighting strength, and could be made to drop beef and milk too. But as the saying goes, they eat and drink like an ox and a horse, so the feed would likely devour considerable energy. Water uses energy as well, naturally."

"Was the water from the Core too?"

"Water and air are supplied from deep within the earth, but the energy source for transporting them is, of course, the World Core."

"Air?"

"If air weren't supplied, a cave-type dungeon would run out of oxygen. And since this world itself is barren, if air weren't supplied from the dungeon, everyone would eventually suffocate."

Incidentally, this dungeon supplies no gas and can't use open flame, so oil boilers, gas water heaters, and gas air-conditioning are nothing but scrap iron.

[Tier-Group 3, Floor 1]

"So this is the main entrance. Equivalent to the eleventh floor, in other words."

"There's a plaza in front of the entrance, but it has no fencing and is dangerous, so once we have dungeon energy to spare, let's attach something as dungeon structure. The planters and pond were probably originally flower beds. There are no plants, though."

"There's a restaurant, too."

"If only we could summon cooking… We can't at the moment, but I don't know whether it's fundamentally impossible or whether it becomes possible once we scale up.

That said, Umeda, the Mercantile City, has a vast number of shops, yet no actual merchandise circulates, which makes me think that even quite large-scale dungeons may not be able to summon what's in their attached facilities. There may be some simple but easily overlooked condition."

"Maybe it's just absurdly far away?"

"This library is in the Japanese cultural sphere, and so is Umeda, the Mercantile City, so I don't think it's all that far."

[Tier-Group 3, Rooftop Garden]

"It's a rooftop garden… with nothing planted in it."

"Living things can't be summoned directly, can they."

"True, when summoning a library, it would be troublesome if we summoned the patrons inside it along with it. Since it's a replication, if we sent them back to the original world there'd be two of them."

"Still, the problem is that we can summon books but can't summon the skills people have acquired."

"That is entirely the Master's fault."

"The Core Room gets relocated over here, doesn't it."

"Its height is matched to the rooftop, and it's atop the original air-conditioning unit space. The cooling tower, which is too tall to fit, has been moved onto the roof of the Core Room. From a high vantage it would look as if it's above the rooftop, but there's no such vantage anywhere nearby, so it's not a problem."

"Will a hole open up where the Tier-Group 1 Core Room used to be?"

"To begin with, a library never has anything called a 'Core Room.' Even the Core Room up to now was merely attached to the side of Tier-Group 1, at the service entrance. An ordinary public library has no fine living quarters."

"It was there from the start, so I never noticed."

"Of course, in some dungeons a facility that existed from the start becomes the Core Room. According to the 'Encyclopedia Dungeonica,' in Umeda, the Mercantile City, the original stationmaster's office became the Core Room. So there are many Core Rooms, but it seems their livability amounts to little more than having a nap room."

[Tier-Group 3, Rooftop Observation Deck]

Going up the stairs from the rooftop, there's an observation deck atop the penthouse.

"I brought soil up here and, by reconfiguring the dungeon, planted the World Tree."

"So that's equivalent to the twenty-fourth or twenty-fifth floor."

"This dungeon itself sits atop a hill, so it comes to about 200 meters in height. There's ample height that the hill itself won't block, so if this world is flat or a sufficiently large sphere, then in theory a radius of forty to fifty kilometers can be monitored. There's the matter of camera resolution, of course."

"So if bandits come like the other day, there's time to sound the alarm."

"If the opponent is infantry, we'll know the day before, but only as an alarm. We'll be expanding the fields from here on, so we'll also have to consider means of protecting the crops. And while it's true no horses have even been confirmed so far, I can't declare with certainty that there's no force out there with tanks or aircraft."

"Dungeon structure is sturdy, but I wonder if it can withstand a tank."

"Who knows. It can apparently withstand a charging dinosaur, but a dragon is ultimately just a big bird."

"Dragoons, then."

"No, Master. A 'dragoon' is 'cavalry armed with firearms,' and what they ride may be a horse, a dragon, or anything at all.

That said, making a creature that physically can't fly take to the air requires a dungeon's unique law, and unique laws only function within the dungeon's sphere of influence, so there's no need to worry about dragons flying in to attack. In theory you could use a large pterosaur as a living hang glider, though."

"Couldn't we install something here, like the telescopes you find on an observation deck?"

"It's certainly possible. If we can obtain a telescope."

"That's the problem, isn't it. Just how far do a library's fixtures and fittings extend?"

"I don't know. The British Library, for instance, was originally an annex of the British Museum, so somewhere down the line a museum may become summonable. And to begin with, a university library is itself a facility of the university, so perhaps an affiliated hospital, a training workshop, or a farm could be summoned. But at this point I can't say."

[Core Room]

"Master, the tasks ahead are coming into view."

"But there's a limit to what books alone can do, and it's not as though it'll all sort itself out right away. Is that it."

"First comes summoning a doctor."