But truth is not the only thing hidden in these subterranean halls. Like the previous two instances, the basement is infested with thingsects that now hide amongst the items left behind by its recent inhabitants. Finding the story behind their origin would mean braving a hive of hidden bugs, never knowing where one might be in wait. But doing so is the only means to discover where the thingsects came from, why they have appeared where they have, and who might be behind it all.

The Thingsect Plot

The basement contains the final clues to the story behind the thingsects. Combined with the shreds of information found in the bank and store, the characters can assemble a loose understanding of what happened and who is responsible. The true story of the thingsect infestations is the following:

Some time ago, a noble by the name of Horatio Alstaan sought to gain power by acquiring a majority stake in the city’s most elite bank. His plan was to anonymously assemble members of a dwindling thieves’ guild with the lure of a heist that would earn them enough gold and renown to rekindle their dying guild. Those who accepted were to meet in an abandoned hideout hidden under a store that Alstaan had bought distant ownership of. 

The assembled crew was given the time that a deposit would be delivered to the vaults, and a pouch of tiny eggs that they were to sneak onto the incoming items. The delivery came from Alstaan himself and was perfectly timed to allow the eggs to hatch into thingsects and spread before they could be discovered. 

His plan was for this to trigger a crisis and force the bank to seek help from the city guard, who would require the relocation of the many vaults’ contents in order to safely deal with the infestation. Guard presence along the delivery route would be conveniently thin, thanks to Alstaan’s other connections, allowing the contracted thieves to pounce on the transports and make off with untold riches.

While coming at the cost of his own stolen valuables, this plan would see Alstaan gain far more. If successful, the theft would diminish trust in the bank and cause other noble families to cease their patronage and investments. This would create an opening for Horatio to swoop in, ever the hero of enterprise, and fund the bank’s continued operation in exchange for a controlling share.

Success would see Alstaan become far richer than he has ever been, while failure would only mean the arrests of a few lingering thieves. Neither possibility should have had any chance of Horatio’s involvement being discovered. At least, that is if everything had gone according to his plan.

The critical misstep was not Alstaan’s, but the thieves’. They succeeded in the first step of infesting the vaults by planting the eggs on Alstaan’s delivery. But the thieves then chose to celebrate with ale, and loosening inhibitions led to the overlooked loosening of a pouch’s tie; the same pouch containing the thingsect eggs. This minute oversight allowed thingsects to spread into the thieves’ hideout and then into the store upstairs. The hideout was infested by the time of the thieves’ next gathering, which they quickly and painfully discovered. The group fled, unsure of whether to abandon the plot altogether. The bank’s head coinkeeper, meanwhile, turned to unaffiliated adventurers rather than the guard, preventing the need for the vaults’ contents to be moved. Now, with his plan already crumbling, all that remains is for Alstaan himself to be exposed as the mastermind.

It is unlikely that the characters will discover every detail of the plot. Doing so would not only require finding every possible clue but also putting them together with knowledge of the city itself. It is more likely that they will form a loose understanding of the events from whatever clues they find, which may not include Alstaan’s name. Fortunately, this does not mean ‘failing’ the adventure. Lucallius Vaurefelt’s own investigation following the bank encounter can be used to supplement the party’s findings and narrow the search to Alstaan. This can be achieved by the party returning to Vaurefelt or the coinkeeper himself contacting them. Byron Marlson can be similarly convinced to help. The characters or their allies can then pass the information on to a trusted member of the guard who is uncorrupted by the nobility, who can then fill in any additional gaps before pursuing Alstaan’s arrest.

The Basement Outpost

The ladder descends into a basement corridor paved with weathered stone. This path continues down several sets of steps, then turns a corner into an open room aglow with candlelight. The chamber is set like a tavern, with a bar top to serve from the barrels and kitchen tucked behind it, and three separate seating areas for patrons, all stained with the concocted smell of alcohol, candle smoke, and damp stone and wood. Plates of leftover food rest coldly on the tables, combining eerily with the silence that fills the room and whatever awaits beyond its three other exits.

The thieves’ outpost is a basement complex hidden beneath the Patched Satchel Trading Post. It is an expansive hideout replete with living and eating areas, storage, and even a permanent teleportation circle. These areas have not seen use in many years and have thus been left to disrepair, the evidence of its recent inhabitants contrasting against dust and degradation.

In its heyday of almost unparalleled success, the outpost was one of the guild’s foremost hideouts. This activity required space for assembled crews to live while planning their work and justified the inclusion of such amenities as a teleportation circle that was employed for getaways in the guild’s most daring operations. Its importance is also why it was never discovered. Only the most trusted guild members knew of its existence, and none were willing to face the consequences of revealing it to authorities upon their capture.

History has since repeated, with thieves occupying and then abandoning the outpost, leaving behind food and other supplies that betray the space’s recent use. It is among these items that the thingsects hide. The outpost’s current infestation has spread into every room, the smallest of their number even creeping through locked doors, and assumed their roles as mundane objects in the hideout’s connected spaces.

The outpost’s subterranean structure is centered around an open common area. This was modeled on a tavern and attached kitchen, with several seating areas and a bar for crews to eat and mingle between jobs. It was then used by Byron Marlson for the Patched Satchel’s storage. The thieves who have since occupied the hideout once again used the space for celebrating their initial success before leaving behind unfinished food and drinks as they escaped the thingsects.

To one side of the central room is a sleeping area with numerous beds, which itself connects to a small room with a fountain and table that thieves would use to appeal to whichever god of luck, bounty, or protection they thought might listen. 

The opposing wing features a private bedroom that was dedicated to the highest-ranking member inhabiting the space at any time. A hallway connects this room to the mess hall, and continues in one direction to a basic storage room that itself extends with two rows of cells used for the rare occasions in which the guild needed to keep animals or even captives. The opposite end of the hall leads to a meeting room with a long table surrounded by eight chairs. The teleportation circle is sequestered in its own chamber between this meeting area and the fountain room.

Entrances and exits. The trapdoor found in the back room of the Patched Satchel descends via ladder into a corridor that leads into the hideout’s central room. A second ladder is placed in the small corridor connecting the central room to the portal chamber. It exits out of a hatch hidden in the alleyway behind the store.

Ceilings and lights. The outpost’s ceilings are all 15 feet high, arching slightly where they meet the walls. The central room is filled with bright light from candles and lanterns, while the sleeping area, meeting room, and storage room are lit only by candles, filling them with dim light. The other rooms are unlit, leaving them in darkness.

Locked doors. Most of the hideout’s doors have been locked since the Patched Satchel was sold to Byron Marlson. Byron made no effort to open them, and the current group of thieves has only accessed the rooms they have needed and kept the door to the storage room locked. As such, the doors to the fountain room, teleportation circle chamber, and larger bedroom are all locked (requiring a successful DC 15 Dexterity check with thieves’ tools to pick). The door to the storage room is locked by a lock louse.

Signs of life. Characters investigating the hideout are sure to discover evidence of its recent use. The clearest sign is the hideout’s candles, many of which are still lit, and the lack of dust covering the following spaces and items. 

These signs are obvious in the central mess hall, as the room is largely clean of dust and cobwebs, food has been left in the kitchen and on plates, and one of the barrels holds ale. The attached kitchen is stocked with enough food to feed at least a small group of people. A character who succeeds on a DC 12 Intelligence (Investigation) check of the food stores also notices that they have been diminished, suggesting that whoever inhabited the hideout had been using it for several days.

A character who enters the sleeping area sees that five of the seven beds are obviously disheveled, while some have books left on the tables beside them. These books are mundane save for one, which is clearly encoded and has a quill and ink well beside it, the ink inside still wet. A character who understands thieves’ cant is able to read this code, discovering it to be a personal journal detailing the author’s dreams.

The meeting room is similarly used, with burning candles and ink wells that have been freshly used. Tables set against the walls also have arrangements of tools placed atop them, including thieves’ tools, tinker’s tools, and pouches of ball bearings and caltrops, arranged neatly as if they were being counted or divided.

Abandoned papers. In their rush to leave, the thieves left a number of papers in the hideout. Investigating these may reveal information about the group, their plot, and the goings on in the basement.

The first of these is a note that is pinned to a support column in the central tavern area. It reads the following:

A series of papers was also left on the table of the meeting room. The largest of these is a map that recognizably depicts the city, with several lines and points marked on it. These markings include the following:

• The location of the Patched Satchel is circled.
• A line is drawn, tracing from a large manor to the city’s bank, the same that was previously infested with thingsects. A character that is familiar with the city or that succeeds on a DC 12 Intelligence check recognizes that the house is that of the Alstaan family.
• A second line connects the same bank with a guard outpost some distance away. A character that succeeds on a DC 12 Intelligence (Investigation) check notices that this path avoids main roads at the cost of time, instead favoring areas that are open but less populated.
• The two lines both have one point along them that is marked. The mark on the line from the manor has three smaller marks surrounding it, while the mark on the other line has five smaller symbols. These icons are all positioned along the perimeter of the respective road.
  A character that understands thieves’ cant or that succeeds on a DC 15 Intelligence (Investigation) check ascertains that these larger symbols are indicating the location an operation was planned to take place, with the smaller symbols marking positions for those involved.

Scattered atop and beside the map are several other papers. These include the following:

• A copy of the letter from the Alstaan house to the city bank, organizing the delivery and deposit of new items to the family vault. The letter includes the date of the delivery but does not describe the path it would take through the city.
• A pair of letters of instruction from United Merchants Holdings, detailing the removal of stock from the basement following the Patched Satchel’s acquisition. The first of these is the same as the one found upstairs addressed to Byron Marlson, instructing him to have the basement cleared of most stock. 
• Beneath this is a second letter, also from United Merchants, but instead addressed to the workers assigned to inspect and oversee the Satchel’s transfer of ownership. It includes an inspection of the store and basement, with intentions for renovations and developments made to the latter. This includes two dates that the workers will return for further planning.
  A character that reads this and the first letter and who succeeds on a DC 11 Intelligence (Investigation) check notices that the first return date is the same day as the delivery from the manor to the bank. The second date is within a day or two of when the party was hired to clear the thingsects from the bank vaults.
  A character that understands thieves’ cant notices that the phrasing of this letter seems to conceal hidden messages. Reading slowly through the letter allows them to piece together the following information:
  • The phrase “package waiting storeroom”
  • The date of the Alstaan delivery, which is marked as both a target and an allied insider
  • The second date is also marked as a target

Keyring. A ring of keys has been left on the meeting room table beside the papers. It holds six keys, each one corresponding to the locks of a different room within the hideout. Each key is also marked with a different symbol. A character who understands thieves’ cant recognizes that these symbols correspond to the respective rooms, labeling them as ‘storage’, ’leader’, ’meeting’, ’escape’, ’tithe’, and ‘rest’.

The keys alone won’t tell the party which locked room is which, even if they understand the symbols. Identifying the rooms will require testing the locks and finding which key fits. Doing so may come with its own dangers, of course, if any of those locks happen to be a lock louse…

Remember the presence of the thingsects when describing how the characters see and interact with the hideout. The items specifically mentioned above are only those that are actually objects, which thingsects should be hiding amongst. This means that there will be additional books, tools, and seemingly full barrels in addition to those mentioned, depending on the thingsects you choose to include.

Map & Asset Downloads

The thieves’ basement outpost is based on our very own ‘Underground Outpost’ battle map, which comes with everything that a secretive guild might need for whatever crimes they get up to. If you’d prefer to assemble your own map, we also have a variety of different resources for constructing the ideal hideout to suit your needs…

Hideout Thingsects

Errant thingsects infest the hideout. They have spread from their containment and hidden amongst the decorations left behind by both the current thieves and those that once inhabited the basement. Their forms are as varied as ever, from unassuming candles to entire barrels, and with the advantage of having no inventory or stock list to expose where they might be hiding.

Candle Crawler

CR 1/4

The candles and collected wax peel free from the surface in one contiguous piece. Sections of the wax underneath separate, exposing it as glistening chitin that covers crab-like legs and a pair of large, chittering claws. Beady black eyes peak out from underneath the wax, blinking inquisitively as the candles’ flames glow brighter.

The candle crawler is a crab-like thingsect with a resemblance to a cluster of wax candles. These ‘candles’ are in fact an exoskeletal shell that both protects the crawler and vents gas generated within its body. This gas leaks only enough to produce a small flame, ignited by a reaction with the air, but can also be expelled in violent, flaming bursts to burn anything too close to the crawler.

Pouchworm

CR 1/4

The leather contracts and then expands, the pouch flexing like an inflating lung. This convulsing wriggles it forward as teeth slip from the seams of its opening, protruding in a circular mouth that grows slick with an unknown fluid.

Perhaps the strangest thingsect is the pouchworm. Mimicking the appearance of a leather pouch, sack, or similar bag, the worm can loosen and widen its body to disguise itself. It can then release various enticing scents into the air to give the illusion that it contains food, flowers, or anything else that might attract prey. And should their victim be particularly unlucky, they may also hear the jingling of gold from inside the pouch, as the worm’s bag-shaped body allows it to hide swarms of coin carrions, bearing bugs, or caltrop creepers, ready to release them directly onto anything that falls for the trap.

Once the worm has a target, its attack is perhaps closer to a cloaker than a traditional insect. It envelopes the target’s head within its body and sinks its teeth into their neck, disorienting them while its digestive acids begin their gruesome work.

Letterdoptera

CR 1/2

The book’s pages suddenly shiver as its covers drift slowly together, then apart again. It rights itself onto its spine, held up by six legs that have unfurled from the binding, while an antennaed head appears at one end. Its movement then abruptly quickens, the cover becoming fluttering wings that carry the creature into the air as the pages on its back shift with curious independence.

Most thingsects abandon their eggs to hatch and grow on their own. This avoids the young being influenced by their parents’ disguise, instead allowing them to independently adapt to the nearest, most plentiful items. But there is a curious exception to this in the letterdoptera. 

The letterdoptera, or occasionally ‘letterfly’, is a close, larger cousin to the parchment pest. It is a moth-like thingsect that appears to take the form of a book, with a special proclivity for spellbooks. Yet the letterdoptera is in fact only the tome’s cover. The pages are its many children, whose wings mimic details such as images, words, and diagrams with exacting detail, betrayed only by repeated pages or details revealed under close inspection. They live on their parent’s back, protected by its wings until they grow old enough to have a brood of their own.

When threatened or hunting, the letterdoptera and its young work in vicious unison. It acts as its children’s protector, while they fly out one at a time to cut targets with the razor edges of their wings, returning to share any spilled blood with their many siblings. Strangely, the letterdoptera seems to prefer the taste of those gifted with magic, usually seeking out spellcasters as their first target. And should their quarry attempt to cast a spell, the letterdoptera’s pages may scatter into the air, distracting the caster with blurring, fluttering diagrams in an attempt to disrupt the casting.

CR 1

A strangely familiar noise sounds out; the rattling of a cutlery drawer. Metal and wood clang together as the tools jitter, lifted by insectoid legs as mandibles and antennae separate from the material. They turn, tiny black eyes fixing on you and blades and prongs aimed in your direction.

When adapting to their environment, thingsects evolve to mimic the closest or most numerous items, developing natural weapons and defense mechanisms derived from the form they take. They do not seek out objects that are ordinarily dangerous. But sometimes the stars align, eggs hatch, and a group of thingsects form a swarm of toolmites.

Toolmites are thingsects that have evolved to mimic their namesake tools, lockpicks, cutlery, and even small weapons. Like the termites they are named for, toolmites most often subsist on wood or similar matter, using the horns that form the striking surfaces of their disguises to scrape bite-sized pieces away. But they are not without a taste for flesh. Toolmites may also swarm together to make up for their size, attacking far larger creatures by battering, cutting, and stabbing prey with the naturally dangerous shapes of their bodies. The sharper toolmites are even known to pin their targets to surfaces, allowing the rest of the swarm to feed without interruption.

Kegerpillar

CR 2

The barrel distorts, its treated wood stretching into bulbous lengths of ligneous hide. Each section of the emerging creature’s body seems to reveal a pair of short, thick legs that protrude from the central mass. Antennae extend as its body lengthens, the barrel now in the wriggling shape of an enormous caterpillar.

The largest thingsect is the kegerpillar. Able to exceed the size of an adult human, the kegerpillar is a hulking grub that hides itself by contracting its body into the shape of a keg or barrel. It can remain dormant in this way for as long as it needs, hibernating until prey wanders nearby.

While resting, the kegerpillar produces an unusual venom from a spigot-like organ that protrudes from its hidden mouth. The clear, watery liquid has a potently intoxicating effect when imbibed, able to loosen the lips and double the vision of even the most ale-hardened sailors. Anyone sporting only a mortal aptitude for alcohol may be affected badly enough to lose consciousness. The kegerpillar can also spit this venom when threatened, its potency allowing it to affect targets without the need for direct consumption. This, along with its naturally wooden hide and generally terrifying appearance, makes the kegerpillar a credible threat even after it is discovered.

Soporific sip. The kegerpillar’s venom renders targets tipsy on contact and is even more effective when drank. A creature that drinks a kegerpillar’s venom makes the same saving throw as if hit by the kegerpillar’s spigot spit attack. The creature has disadvantage on its saving throw, the poison effect lasts for 1 hour instead of 1 minute on a failed save, and the creature does not repeat its saving throw at the end of each of its turns. On a failure of 5 or more, the creature falls unconscious for 1 hour instead of 1 minute.

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