Subterra is the realm of various caverns, tunnels, and deep spaces below the continent of Eryst. It is populated by a variety of species and races.

Before the First Era, most regions of Subterra had not been explored and much of the realm was home to dangerous wild species and monsters.

During the First Era, with the population of Eryst on the rise, many cultures with a natural affinity for being underground chose to expand their cities in the direction of Subterra. The largest cities now contain a range of surface communities, semi-underground communities, and fully Subterran communities. Smaller settlements were not as capable of the construction and mining required to expand their existing town, and many chose to abandon the surface in favor of a Subterran existence.

Explorers, map-makers, and adventurers were at the frontlines of the initial expansion into Subterra. As underground regions were explored, outposts were constructed that grew into settlements and eventually towns and cities. And so the wild areas of Subterra were gradually tamed, with much of the natural flora being domesticated and adapted to support the underground communities; mushrooms in particular are a staple for nearly every Subterran.

The relatively rapid expansion of communities into what was previously a dangerous realm has left its mark on many of the cultures. The organized and “good” cultures were most effective at working together to build lasting communities.

By the Second Era, most chaotic or evil cultures in Subterra have only been able to remain on the fringes of the realm, having been steadily pushed back by the armies of the more respectable and law-abiding cultures. Most cultures in Subterra consider lawfulness and respect for one’s fellow beings to be of great importance.

In the Second Era, most regions of Subterra are safe and civilized, with well-maintained roads and law-abiding citizenry. Trade in Subterra is regulated by most cities and often heavily taxed to pay for the upkeep of necessary infrastructure. Although Subterra is often the safest route for traders, trading routes on the surface can offer the potential for more profit for those willing to take the risks.