Trapped above by Arul Sylax and his allies, the only way to escape is either through through the cistern or the secret door on the lowest level. This leads to a fairly festersome series of descending caverns leading to a small watercourse that drains downward. The connecting cavern is inhabited by a micro-ecology of fungi, piercers and carrion crawlers, and the burrow of an Umberhulk. If the PC's continue onward, they will eventually discover the exit into the Far Below, a vast network of caves stretching most of the length of the FarSpar mountains.
Cistern Pit - Violet Fungi in bottom, upward path is caved in.
Chamber 1 - Down a sloping path, leads to an empty chamber of considerable size, where a burrowing umberhulk lies dormant just inside one wall. It will attack when the party has passed it.
Long Drop - The PC's will not be able to get down unless they cannibalize the cistern chain. Then a DC-15 Climb will allow them to reach the bottom. Failure is a fall equal to "Margin of failure d6", max 10d6.
Chamber 2 - This large chamber is home to a pair of Cave Fishers, who live in the crevices up at the top. The floor is covered in rubble and small boulders, 1/2 move, and lots of bones, chitinous scraps, and even some treasure.
Exit to Far Below - Down still further is an end to the tunnel. Blocked with a web of slimy fungus, it can either be burned or cut, though either one provokes a swarm of disgusting flying "things", stats as a swarm of wasps. Past this curtain lies a great chamber of the Far Below.
Typical major caves are 1d4-1 miles wide, and 1d6 miles long, with connecting tunnels and 1d4-1 settlements of various sizes. many have waterways of some sort, especially small pools and ponds, though a few of the deepest ones have actual lakes of considerable depth. major caves are connected by warrens of tunnels, either natural ones (if a watercourse), or tunnels dug by ravenous Purple Worms.
Wilderness - Whether vast fungal forests or barren side caverns, these are regions unclaimed by civilized beings. They are home to Troglodytes, which live in upper parts of the Far Below, Quaggoths, which dwell in the chasms and rifts of the region, and the occasional Myconid circle. They are joined by all manner of beasts. Animals are large and pale, feeding on fungi if herbivorous, or anything at all of carnivorous. Giant Spiders, Carrion Crawlers, Gricks, Deep Ankhegs, and Hook Horrors are the most common. Aerial predators include Cloakers and Giant Bats. Otyughs are a bit like bears in the Far Below. Lakes are inhabited by blind, pale arthropods, (use Giant Scorpions without poison) for stats. In addition to the various beasts are "hermits", creatures powerful enough to be left alone. Hags, Ogre Magi, and the like often have small homes in the middle of forests, alternately preying upon or doing business with local settlements. The occasional large lake will be home to an aboleth, usually served by Chuul minions and thralls.
Settled Areas - These areas are marked by roadways or at least paths through the fungal forests, patrols by the residents or their minions, and structures that are built and manned to control access. Duergar are the dwarves who moved deep below ground in millennia past. They are the dominant power in many upper regions, living in small free standing towns with forts built into the walls; populations smaller than equivalent Dwarven cities, with slaving economies. At the same level but in smaller chambers live the Svirfneblin, who reside in towns built into the walls of their chambers. Deeper down in the earth, Drow settlements can be found, each one with a well-guarded gateway to the Shadowfell. Deepest of all live the mind flayers, and their kuo-toa and grimlocks slaves and worshippers.
The PC's will discover a fungi forest, encounter a dangerous beast or several, and then run into a party of Svirfneblin (Belwar, Durthmeck, Kronthud, Schneltheck, Thulwar, Walschud) who will escort them back to their camp. They will not take them to their actual settlement, but they will give useful advice about traveling the Far Below, and eventually reaching the surface.
Surface Access:
The PC's will move downslope away from the wall of the cavern, discovering below them a forest of fungi, growing between pillars that reach to the ceiling high above and pools of standing water. While crossing the forest, the ranger will find an obvious game trail which follows a ridge line of moderate elevation. At one of the lower points, where the PC's must wade through some shallow water, they will be attacked by a "Deep Otyugh" - somewhat larger than a normal Otyugh, with some sort of heinous aberrant ability. It will attack from ambush and try to drag a single PC down into it's lair do drown and rot, for later consumption. Once the creature has been dealt with or escaped, the trail will lead to where a party of Svirfs are working busily on a small lump of rock. They will initially be wary, but they are covered by concealed guards with crossbows and acid grenades. If the PC's establish that they want to reach the surface, the Svirfs will direct them to the Duergar town of Ilsombek. It is on the river called Khevartzuf, and while it does not have surface access that they know of, there are many there who might know of such a place to go. While the Svirfs are not able to escort them to Ilsombek, they will happily help the PC's to find a way to the river. The Svirfs will escort the PC's to a nearby Myconid circle, as they will know where to go.
The Myconids will agree to assist the PC's in exchange for a task. A pair of humanoids have taken up residence in an old stone structure, and they have bedeviled the Myconids for a long time - the Myconids only know the threat as "tall dark ones". Certain parts of the forest have acquired an evil cast, because a Night Hag named Forekstraka resides here. She now lives with her Oni mate Kereghurk in a stone fort built on a small rise. They have disguised themselves as a pair of Drow exiles, and will play up the "driven out because we were not evil enough" angle. They will welcome the PC's to their abode, and act glad to have guests. If the PC's will rid them of this menace, they will craft transport and provide provisions and guidance, including a map and luminiferous fungi that will discourage certain predators in the water for a while.
Eventually the PC's will reach the Cataracts of Ilsombek, where the Duergar have a town (also known as Ilsombek). There is a wall and gate blocking access through the tunnel outside of the falls themselves. The PC's must pay a toll, fight their way through, or sneak past. All must pay if they want to pass. If the PC's pay an extortionate toll, they will be allowed access to the tunnel down to the main town, a thirty minute ride that will allow them to carry their dugouts with them. From the tunnel, they will eventually see the vast lake that lies ahead of them . It is a mining and forge town, with a population of a couple of thousand Duergar and slaves, as well as a small number of one-off weirdos. The town is actually ruled by House Kluthruel, an exiled Drow clan that conquered the area many years ago. The Drow have a unit of Quaggoth servitors as muscle, but there are also ogres hired by the Duergar to mind their slaves and act as guards. Duergar built areas are angular, blocky, and harsh, while the Drow castle is elegant and spooky looking.
In the town, coin will buy them secure lodging until they can discover the way to the surface. There is only one inn that will serve surface worlders, the "Moldy Medusa". It is run by a Tiefling former pirate captain named Harkron, along with her two bugbear guards (stats as Veteran). Once they get settled in, socializing will let them know that there is a way home on the other end of the lake - the Hobgoblin fortress of Hurg-Razad. The PC's can cross the lake (use Loch Ness as pattern for size), either in their little boat (unwise), or take passage on a Duergar galley (Captain Ghramesh and "Terror of the Lake") headed south, to be deposited on the shore nearest Hurg-Razad. Captain Ghramesh will not land on the shore, as he regards the entire area as bad news.
The abandoned Hobgoblin fortress of Hurg-Razad was built many centuries ago by a now-extinct Northern Hobgoblin kingdom. The fortress itself was used to dominate both the surface region and the area around the lake. The kingdom was destroyed in the war that ended Fermas Vorokhoi around -200 IY, and has been left mostly abandoned since then. The surface construction was razed to the ground, but the subterranean areas are still somewhat intact. The layout of the intact portion is essentially a bit like Helm's Deep, but underground. An outer wall lies in ruins, with an inner bailey and a series of galleries up the cave wall as archery chambers. The interior is divided into three primary sections:
The Fortress: This area is designed to secure the entrance and dominate the surrounding terrain, but it has been badly damaged by earthquakes over the centuries. It consists largely of barracks, fighting positions, and a few internal assembly areas. The fort is inhabited by the Hobgoblin Warlord "Kirgot", armed with a Vorokhoi longsword (crit on 19-20), and his Hobgoblin warriors. The last survivors of Castle Vizesces, they escaped the slaughter by heading north into the mountains, and eventually headed to some place familiar. In the process, they wound up having to fight their way down here. Kirgot is accompanied by two captains, thirty-five common soldiers, two ranger archers (+3 to archery, "Alarm", "Hunter's Mark", and "Fog Cloud'), and three bugbears, as well as some captives taken along the way. Kirgot intends to take over this part of the Far Below and gain glory that way, since the Pine March war is lost. They have sealed off the main doors to the rest of the complex, and are currently ensconced on the upper level of the fort, with rangers watching the lake. Unless the PC's are careful, they will have a fight waiting for them. Kirgot also managed to retain control of five Bane Zombies, using his amulet.
The hallway to the main complex has been trapped thoroughly with the limited supplies the hobgoblins have, mostly with noisy deadfalls. the inner door itself has been rigged to drop a barrel of oil and firestarting chemicals... 2d6 fire per round in the hallway. The door is also jammed closed, DC-20 STR roll to open. Furthermore, the ceiling and walls are pierced with murderholes - six hobgoblins with longbows will fire on intruders, two from each side and two above will fire at them as they come, under 3/4 cover (+5 to AC and saves). Bow attacks are +4, 1d8+1 damage. The first time a PC attempts to attack in melee through the slot, a bugbear will attack with a spear, +5, doing 2d8+2 damage, plus +2d6 if it makes the Stealth+6 roll.
The rest of the complex has been thoroughly damaged by time, battle, and neglect. It includes a great hall, an assembly area, stables, armories, forges, chambers for captains and chiefs, slave pens, shrines to various dark gods, and the facilities needed to supply a garrison of some size. The PC's will have to make their way through to reach the stairway. Even a brief examination shows that the original builders were dwarves, but that it has been added to over time. The reason travelers avoid the region is that a pack of trolls has made its home here, hunting in the caverns, and preying on the occasional travelers. They found a way out through a ventilation shaft leading to the caverns. They had an invigorating battle with the hobgoblins when they arrived, but both groups now avoid interaction with one another. They will be thrilled by more visitors to play with.
The other wing of the complex is mostly abandoned, ceiling collapsed and hallways blocked with rubble. If the PC's decide to climb in, they will find the area has nothing but green slime, cave vermin, and a Black Pudding that slimed in through cracks in the walls. Each main wing leads to a staircase that goes up, intertwining but not joining with the other staircase except on one of three landing floors. Each landing floor has something special. Making matters worse, the shaft is infested with Cave Fishers, which feed on bats and other vermin.
The shaft is about 1200' feet high. It will take about an hour, and will require a CON Check DC-15, to avoid being "Exhausted" if they press on. Once before each landing, everyone must make an Acrobatics or Athletics check at DC-12 to pass weakened portions of the stairwell safely. Anyone falling will fall (2d6-2 x 10) feet (min 20ft) before they get to make an Athletics or Acrobatics save at DC-15 to stop their fall. Success means they have landed in a giant spider web, and will be visited within 1d6 rounds by a spider or a cave fisher. Failure means they fall again, and another opportunity. After a third time, they will land in a web and stop.
Lowest - At the first landing lives a Drider spellcaster (Drisintra) and her minions. She is accompanied by several giant spiders, and they freely travel the shaft to hunt. The trolls have learned to leave her alone, as she has a wand of fireballs that she is happy to use. She has accumulated some minor treasures, which are stored in her chambers.
Middle - A pair of Umberhulks have burrowed in here, where they prey on travelers on the shaft. Their crumbling burrow will eventually lead to the main cavern system far below. Just above this landing, the stairs have collapsed, and will have to either be climbed (Athletics Checks and lots of falls) or switched over to the other one.
Highest - Finally near the surface, this last landing is partially unstable, but a safe path can be picked through. The gnawed remains of several dead hobgoblins and a bugbear can be found here, trapped under collapsed rubble. If the PC's make any noises, they will be attacked by a group of carrion crawlers that are feeding here.
Surface - On the surface level, the PC's will find a complex very similar to the one deep below ground. This one has been badly damaged by cave-ins and neglect. All throughout it are signs of neglect and battle, and the mangled and gnawed carcasses of numerous bandits, all of Pershamon derivation. Slain by the hobgoblin company, they were then set upon by the ghouls and ghasts that have followed the legion since they departed Pine March. A few nuisance ghouls will attack the PC's, easily dispatched. Eventually, the PC's will stumble out of the caves into a mountain valley. They won't know where they are, but traveling downstream will lead them to a Pershamon village. They will be spotted by guards, and challenged by five armored riders, one lancer and four horse archers - Lord Surawhala and his retainers. Once he determines they are on the level, he will invite them to his steading, and offer to escort them to Ecmen in a couple of days. Here, they can reunite with Molfin Boltgrind and his airship. He can take them further on, as he is happy not to have to tangle with a dragon.
The PC's will be unable to return the Stony Gift to Prince Marath, but he would likely tell them to continue their quest anyhow. If they decide to wait in Ecmen, they can send him a message and get a reply via Sending. If this is done, he will tell them to wait in Ecmen for his man, a monk named Sothkei. The monk will arrive within the week, and will take the Stony Gift. He will also deliver payment, and a message that they should continue on their quest and waste no more time.