Commentary: About the Human Farm

This is purely a note on the setting. It has little bearing on the main story.

A dungeon does earn some natural income from its own height, or depth, but in the main it gains dungeon energy by defeating people (be they human, Beast, or Asura) or by harvesting their emotions for energy. For this reason a dungeon, whether by design or by instinct, lures in adventurers, bestowing treasure upon them and setting monsters loose against them. It is also necessary, now and again, for an adventurer to die within the dungeon; but since a dungeon of ordinary size needs only a small number of dead, there is another method too, one that keeps the dungeon's own danger level low while demanding sacrifices from the villages near its sphere of influence.

Plants and animals other than sapient lifeforms contribute nothing to dungeon energy.

A human farm gains energy by settling residents inside the dungeon and providing them food, clothing, and shelter. As for the "defeating" side, one need only wait for their lifespans to run out on their own. Regardless of whether they are good or evil, a so-called "great" personage yields more energy upon death; so the arrangement most convenient for a human farm is for the dungeon to be used as a fortress or a temple or shrine, where generals and high priests pass away of old age.

Rather than settling people, one may instead confine them, torturing and tormenting them; but keeping prisoners in good condition over long stretches while collecting emotional energy requires a great many jailer-monsters, which means upkeep costs, and since the Named monsters and named ordinary monsters needed to manage the other monsters are limited in number, the difficulty runs high. For this reason, dungeons that rely on a prison as their chief energy source are rare.

Even the non-confining sort of human farm runs short of personnel if the dungeon side has to furnish the governing apparatus itself. Moreover, dungeon monsters only consume energy, whereas hired soldiers and laborers supply dungeon energy merely by existing, weeping and laughing and eating; so management is often delegated largely to the residents. In Umeda, the Mercantile City, the merchants do the managing and the dungeon confines itself to leasing out the space, while in Asuka, the Temple of Stone, the dungeon's involvement amounts to no more than handing down oracles. Nasu Daizen-no-daibu, who styles himself with an official rank and stands at the head of operations, and Shiso, Director of Books (Marie) are the exceptions, but even so the great majority of those beneath them are residents hired on a stipend.

As for what kind of residents a human farm keeps, since this world has many humans they tend to be human-centered, but it may also be that, like a livestock ranch, only one particular sort of Beast is kept, or, as at Nasu-Shiobara, both the monsters and the residents are eggplants (Asura).

There is, however, a general problem: a dungeon is an environment poorly suited to habitation. And while of food, clothing, and shelter it is food that is needed in vast quantity, what a dungeon's functions can produce is feed for main-line monsters and their kin; and even a dungeon able to repurpose that for other use would run a massive deficit if it simply generated and supplied food in the ordinary way.

For this reason a human farm must either export some product that requires little dungeon energy yet commands high value in human society, and buy food with the proceeds, or else produce food cheaply by some means.

At Nasu-Shiobara, for example, eggplants (Asura) dwell there, and while fertilizer for Asura can be had, securing water is a struggle.

The Library-City Dungeon, having begun as a library, poses no problem at all as a living environment. As for food production, because water and electricity are supplied in abundance, and because the main-line monsters are Asura so that fertilizers of every kind can be obtained, food can be produced at comparatively low cost so long as there is sunlight. A plant factory would have to light its crops electrically, which makes it the costlier option, so the farmland is spread out on the surface instead.

The fatal flaw of a human farm is this: when the principal residents are human, the residents increase without limit, and the thing is not sustainable.

Humans are easier to obtain than Asura, Beasts, or Pretas, and their fecundity is on another order entirely, so by immigration and breeding their numbers can swell over a short span, and the dungeon can be made to develop rapidly.

But manage humans in a favorable environment and they multiply without end, and in no time the food supply fails to keep pace. Deliberately spreading famine and poverty to curb the increase not only causes the harvested energy to plummet, but sends the risk of revolt soaring. As a rule, a human farm is fated to collapse within three hundred years.

At present the population of the Eight Provinces of Kantō is around five million, of whom some three million are human. According to Malthus, a population doubles every twenty-five years, so in a hundred years the humans will number forty-eight million and the population of the Eight Provinces of Kantō will reach fifty million. In reality the rate of increase slows as crowding sets in, but the dungeon's harvested energy declines all the same, and that becomes the cause of collapse.

Even in this region there was once a human farm that depended for its food on surrounding farmland and on other dungeons, and that exerted a powerful cultural influence over the Eight Provinces of Kantō for nearly three hundred years; but when the dungeon supplying its food fell into decline, it could no longer feed the humans who had multiplied to a million, living standards fell, harvested energy dropped, and the thing broke down and the dungeon collapsed. Because it was a surface-type dungeon, the surviving residents came flooding out and scattered famine and plague across the neighboring lands.

The Library-City Dungeon, with its vast sphere of influence and its high potential for food production, would, should it break down in a population explosion, be unable to avoid a catastrophe on another order of magnitude entirely.

1: The Founding Period of a Human Farm

For one reason or another, a dungeon suited to human habitation comes into being. With production capacity to spare, an uncomplicated organization, and low taxes, the population increases rapidly.

The Library-City Dungeon's stated tax rate of four parts to the lord, six to the people is high for the founding period of a human farm, but the effective rate differs little from that of an ordinary human farm.

2: The Development Period of a Human Farm

As the population grows, culture develops with it, and whether the dungeon manages affairs or the residents do, the governing apparatus grows more advanced and more complex.

At the same time, because management can no longer reach everywhere, dubious new religions spring up and some among the residents stir up disturbances. In response, the bureaucratic machinery swells.

3: The Stagnation Period of a Human Farm

Production fails to keep up with the population's growth, the residents grow more impoverished, and the dungeon's harvested energy starts to run short.

The government attempts reforms, but by this stage it is already too late.

4: The Collapse of a Human Farm

Within three hundred years at the longest, the society inside the dungeon can no longer be maintained, and it collapses, dungeon and all. An underground-type dungeon may take its residents down with it, while a surface-type releases a great flood of refugees and throws the region into chaos.