Beneath Ptolus lie vast chambers, caverns, and tunnels. In fact, there are whole cities of dwarven and dark elven creation below the surface. But how can this be? And why here? There are many reasons, and there is one reason…

The so-called “Dungeon” has many portions: natural caverns, the infamous expanse of Dwarvenhearth, the even older Banewarrens, the extensive Labyrinth of Ghul, various crypts and independent underground complexes, and even the sewers. And then there’s the Undercity Market and environs, which is almost like another district of the surface Ptolus. All have their own reason for being, their own creation stories, and their own particulars.

But the one reason, the ultimate explanation for why they are all here—the Banewarrens, the monster-infested underground Labyrinth, the dark elven grottos, the zaug caverns, and even the vast Spire itself—is the Galchutt.


Unbeknownst to him, Danar Rotansin—who became the Dread One, who built Jabel Shammar and the Banewarrens and caused the Spire’s creation—was drawn here by the subconscious, subtle, seductive power of the Galchutt. Ghul, the Skull-King who built Goth Gulgamel and the vast Labyrinth that radiates out from below the Spire, was brought here because of the legacy of the Dread One, whom he sought to imitate. Even the dwarves who built Dwarvenhearth were tricked into coming here and digging deep.

The Galchutt wanted to be found. They wanted creatures near them to seduce and control even as they slumbered deep below the ground. Their powerful essence worked on the subconscious minds of nearby creatures, and they created servants—those who would follow their empathic suggestions; those who would worship them as gods. Most such servants do not understand the forces that work upon them and are not even aware that the Galchutt exist.

But the presence of the Galchutt serves as a clarion call for every evil beast, chaotic creature, and malevolent monster. Subtly, slowly, the lure has worked on the instincts of creatures from aboleths to yeth hounds. Without knowing why, a disproportionately large percentage of the world’s evil creatures has gathered around or beneath the Spire, drawn by the power of the Galchutt. And as the Galchutt begin to stir and the dreaded Night of Dissolution approaches, the sympathetic pull of their essence only grows stronger. Even non-evil creatures with savage natures, like owlbears and rust monsters, gather here in greater numbers than anywhere else.

The Elder Elves recognized that an evil attraction surrounded the Spire. They saw it affect some of the Charad Titans, and they avoided the area. The dwarves, on the other hand, did not believe the legends of evil surrounding the Spire. They built Dwarvenhearth in its very shadow due to the prevalence of valuable ores. In fact, they grew to believe that the area was not unholy but holy, a place promised to them in their own ancient prophecies. And they still believe that to this day, never guessing that the subconscious power of the Galchutt encouraged them to delve deep into the earth and awaken things that lay sleeping there.

As the Galchutt stir, some believe the pull of evil creatures toward the Spire and the regions beneath it is stronger than ever. Perhaps it is that very pull that plays upon the greed of adventurers, influencing them to venture below the city and disturb what lies beneath.


As stated above, it’s dangerous to lump everything that’s below the city together into a single category. These areas are as different from each other as the Nobles’ Quarter is from the Warrens. However, the biggest differences lie between the areas deemed “Undercity” and those deemed “Dungeon.”


“Dungeons” are not a common concept in the rest of the world. That is to say, dungeons are holes in the ground where prisoners are thrown in the lowest level of the castle, but they are not vast labyrinths filled with treasure and monsters. The concept is unique to Ptolus.

The Undercity is not a discrete place surrounded by neat borders. Instead, it is a collection of all the areas below Ptolus that most closely resemble the aboveground city. Businesses operate here, folks pass through—some people even make their homes here. The popular Undercity Market in these levels caters to delvers and even offers a Dark Market for shadier pursuits. One can find city institutions (the Prison), organizational headquarters (Delver’s Guild, Longfingers thieves’ guild), and more in the Undercity. These levels— some near the surface, some quite deep—are accessed from the surface via public passages, such as the wide staircase in the middle of Delver’s Square in Midtown.

The Undercity also serves as the doorway to the Dungeon: wild areas ripe for exploration and rife with danger. One is liable to find certain features and phenomena throughout the Dungeon that one does not see in the Undercity, such as the Pits of Insanity and chambers of Ghul’s Labyrinth. (These are discussed in greater detail later in this chapter.)

The Dungeon includes several different types of environment:

  • The sewer tunnels, which lie closest to the surface and can connect delvers quickly with other Dungeon areas.
  • The caverns, deep natural cave complexes that are home to dwarves, dark elves, and monsters.
  • And Dwarvenhearth, ancestral stronghold of the Stonemight dwarves, abandoned for centuries.


If the “Undercity” is the settled subterranean areas below Ptolus, how does one refer to the wilder areas down there? Some erroneously call them all Dwarvenhearth or the Banewarrens, but those names refer to specific underground areas, not to the entire belowground world. Some use “the Realms below” or “the Labyrinth.” Others just say “below the city.” The fastest growing term, though, is simply “the Dungeon.”

While the map below may make certain subterranean locations appear quite close together, the distances are more vast than they look. Locations that appear near each other on an east-west axis may be quite distant on a north-south axis. And even nearby locales can feel far away due to the rigors of underground travel and the many switchbacks in the paths between sites.

Dungeon Side View of Ptolus the City by the Spire

It’s All Connected

One very important fact to relate to the players is that many underground areas are connected. A dungeon adventure could exist partially in the cellars of an old manor house and partially in a section of Ghul’s Labyrinth, which the cellars’ original builders broke into inadvertently. Many such connections exist below the city, with one type of underground construction or natural cavern spilling into another. One assumes most connections were unintentional—a construction crew is digging along when suddenly they break into an existing subterranean space. Much of the time, builders would seal up such connections, assuming they were unwanted. Some connections are sealed with a locked door, but others might be completely bricked up. Intrepid delvers carry picks and other digging tools for just such an occasion.


Ptolus is designed to allow you to run a campaign that incorporates urban intrigue adventures with exploratory dungeon-style adventures.

Some groups may prefer to run explore-thedungeon adventures independent of anything going on in the city. The Undercity Market is as close as the characters wish to come to civilization. In such a campaign, the player characters go below the city, perhaps with an explicit goal in mind, or perhaps just with the idea of exploring and finding treasure. They might be interested in a specific area, such as the catacombs below a temple or the underground lair of an aboleth. Or, they might simply want to wander around and see what’s down there.

Other groups integrate urban scenarios with dungeon adventures. A feud with one of the Balacazar crime bosses might lead the PCs to attack his office, only to discover that his actual lair lies beneath the office building in a multilevel underground complex filled with traps and guards. Raiding the subterranean temple of a chaos cult could lead the adventurers into further intrigue when covert cultists in the city exact revenge by framing them for a crime they did not commit. The only thing that will sway a dwarf smith that the PCs negotiate with is a brooch stolen from his family by dark elves, so the characters must travel deep underground to retrieve it for him.

Dungeon adventures can be a part of any Ptolus Campaign, to a lesser or greater degree.


One way to run a Ptolus campaign using the realm beneath the city is to do so sparingly, in small doses. While investigating a Balacazar safe house in Midtown, the player characters find that the cellars below the house extend farther out into a complex of ten secret rooms used for storing loot and keeping prisoners. On another adventure, the PCs explore the crypts below a church in the Temple District, rooting out some unruly ghosts. The entire crypt area involves eight different tombs and the passages that connect them. In the course of a different scenario, the adventurers find that a vampire has holed up within an orphanage in the Guildsman District. When they go in, they discover that she has used the dominated children to dig down into the Labyrinth below the orphanage so she can take a handful of those ancient chambers of Ghul’s minions for her lair.

Over the course of a “small dungeons” campaign, the player characters learn to expect that many locations have extensive underground components. The players may never truly understand the vastness of the subterranean regions, but they will never grow weary in the middle of a long dungeon crawl either. This option is best for groups that are interested in the goings-on in Ptolus itself, desiring only the occasional foray below the streets as a part of their urban adventures.


If the DM and players love big dungeon crawl adventures, Ptolus offers them that as well. Counting everything—from the Banewarrens to the natural caverns, from Ghul’s Labyrinth to Dwarvenhearth, and including all the other subterranean areas below the city, there are countless miles of corridors, chambers, and passages to explore. The different types of subterranean locations mean that even a dungeon-focused game has an almost limitless amount of variety. There’s even the Undercity Market for your resupply needs. In such a campaign, the player characters might use the surface Ptolus primarily as a place to go for healing, rest, and to identify and sell their loot.


The only way that so much can exist in such a small area is that the Dungeon below Ptolus delves down vertically as well as horizontally. One could set two Dungeon adventures practically on top of each other with no link between them, either conceptually or physically. Many Ptolus Dungeon areas do not spread out very far laterally, but involve many levels, one atop the next.