Tunnel Dungeon (RDG)
Tunnel dungeons are densely occupied labyrinthine networks teeming with humanoid inhabitants beneath the surface. Ever-growing due to the ceaseless activities of their denizens, the tunnels and rooms serve as homes, fortresses, and treasure troves. Occupants must protect themselves against threats from both above ground and below, often employing elaborate defenses, traps, and architectural innovations. While treasures abound, stirring up too much attention may cause a group of intruders to become overwhelmed by the sheer number of potential adversaries.
Entrances to these areas serve as pivotal junctures requiring protection to ensure the safety of the inhabitants, many of whom are likely non-combatants, including children, who contribute to the community's productivity. Multiple defensive measures are typically in place, encompassing strategies that may involve personal sacrifice and, crucially, the activation of an alarm. It's worth noting that not all entrances are externally guarded; some tunnel dungeons may appear innocuous to passersby. However, upon entry, individuals should anticipate encountering immediate resistance from defenders within the area.
However, exceptions exist to this pattern. Certain dungeons may remain undisturbed for extended periods, spanning months or even years, leading the inhabitants to grow complacent regarding the need for vigilance. While it's conceivable that a group could enter without encountering any resistance, such occurrences are rare. Typically, guards or sentinels are stationed, poised to apprehend intruders by surprise or to fiercely defend their territory if provoked.
Tunnel Dungeon Entrance
Entrances come in a variety of sizes and forms, serving as essential transitional points from the external environment to the interior of the dungeon. The design of these entryways necessitates a relatively modest outer footprint to avoid drawing undue attention to the dungeon, which could prompt intervention from influential local figures determined to eradicate any perceived threats. By maintaining a discreet external presence, these entrances help to minimize the risk of discovery and subsequent attempts to eliminate the dungeon's inhabitants.
Die rolls indicated are on a d20. Each percentage shown is rolled individually to see if that feature exists. All passages, unless stated otherwise, are 5 ft. wide.
| Roll | Result |
|---|---|
| 01-23 | Large opening into abandoned mine, either level or somewhat sloped (1-15) or occurring as a vertical shaft (16-20). May have covert guards (40%). |
| 24-32 | Palisaded yard, 20 ft. diameter; gate permits access, guarded by evident sentinels. May have one tower (20%). Sealed door into tunnels located within palisade. Replace palisade with stone circle 5% of the time. |
| 33-93 | Small opening, deserted and obscured by vegetation (1-9), amid scattered boulders (10-16), beneath a low, crumbling archway (17-19) or hidden beneath a rusted iron grate (20). |
| 94 | Submerged cave, accessible only by diving beneath the water's surface and swimming through a entranceway passage to an interior, breathable hewn passage. |
| 95-00 | Timbered door set into a rocky face of a cliff. May be barricaded (25%) and/or guarded by 2-4 evident sentinels (50%); otherwise deserted. |
Large openings give way to a long undisturbed passage about 60 ft. in length, which must be traversed before learning what is in space beyond. Outside the abandoned mine, there are bound to be remnants of mine carts, with wooden structures, timber and scattered tools. An investigation should reveal that these have been moved or examined in the recent past. If there are covert guards, these are positioned discreetly, hidden from view among rocks or vegetation, watching the players and waiting for an opportunity to take them by surprise.
Palisaded yards may be half-circles or three-quarter circles, depending on the terrain; the palisade is 15 ft. high. The dungeon door will give way to a 20 ft. passage that slopes downwards at 4-24 degrees. This door is 7 ft. high, 4 ft. wide and 4 in. thick; because it's in constant use, it won't be stuck, barred or bolted. Towers consist of a frame supporting a platform 20 ft. off the ground, 8 ft. wide, with a single archer on top if the tower is present; this is in addition to the 3-8 evident guards that are present. Each is equipped with a horn for giving an alarm. There is a 10% chance for each guard that a chained watch animal is also present. If a stone circle is indicated, this is also 15 ft. high and 2 ft. wide; add an addition 2-4 evident guards. Palisades and stone circles also include a gong for giving an alarm.
Small openings are 2-3 ft. wide and always concealed, requiring 10 to 60 minutes to locate. They are deserted, without guards or sentinels, and are rarely used (if at all) by the residents. There is a 10% chance of a trap being located around the entrance. The narrow opening enters upon a similarly narrow passage that descends 4-10 ft.; from the bottom, the passage continues for 5-20 ft. before reaching the space beyond.
Submerged passages are completely full of water, which may be presumed to be clear. Torches and other illumination sources, however, cannot be lit on the other side without first having an opportunity to dry. The entryway descends 7-12 ft. downwards to a 4-6 ft. wide opening, which continues for 6-18 ft (4d4+2). They open at the top of a passage that's a mere 10 ft. before the inside space.
Timbered doorways consist of a dungeon door without fortification set into the stone exterior as an entranceway into the dungeon. If not barricaded or guarded, there is again a 10% chance of a trap. Inside the door is a 20 ft. passage leading to the inside space.
Initial Space Behind Entrance
This describes the area first encountered once passing through the entrance, occurring at the end of whatever distance has been described under the tunnel entrance, above. This area describes what additional defenses are positioned between the characters and the interior of the habitat, if any. As before, passages are 5 ft. wide and where indicated, are 20 ft. long before a check on the periodic check table is made, below. Where a door is opened, check afterwards on the space beyond door table.
| Roll | Result |
|---|---|
| 01-06 | Alarm; bells and other devices have been rigged throughout the passage to alert inhabitants once an entry has been made. |
| 07-45 | Guardroom; 15 ft. diameter circular room with 2-3 guards that have been posted to monitor and control access to the habitat. Open to the approach passage. Includes furniture, one dungeon door on far side. |
Alarms are clearly visible, serving as a deterrent by their mere presence. Most unintelligent creatures will likely ignore them and trigger the alarms. Navigating through the area without setting off the alarms requires both a dexterity check AND a saving throw vs. breath weapon; to remove the alarm requires an ability to remove traps. If an attempt to disable the alarm fails, a substantial amount of material falls to the floor, alerting the inhabitants to the presence of intruders.
Guardrooms may vary in shape but are unlikely to be larger, since limited convenience of access is part of the room's purpose. The guards are likely to be bored from endless days of "watching," and thus must make a surprise check once the player characters come within 40 ft.; if the guardroom is at the head of a mine tunnel, or if intruders emerging from a submerged tunnel take much time pulling themselves out of the water, this gives them time to recover. Otherwise, a party may potentially overwhelm them before they can act.
