The Underdark
Beneath the kingdoms, forests and mountains of Warlderia lies another inhabited world. Known collectively as the Underdark, it comprises vast caverns, underground rivers, buried cities and passages extending far below the reach of ordinary mines. Its peoples maintain their own settlements, cultivate food, conduct trade and wage wars of which those living above may know almost nothing. The Underdark has no single ruler or common allegiance. Its inhabitants include ancient civilisations, scattered communities, displaced peoples and creatures that recognise no authority beyond their own strength. A traveller may pass from a guarded trading road into an abandoned kingdom, cross a subterranean lake and arrive at a city whose rulers regard surface visitors as customers, intruders or merchandise.
The World Beneath
The Underdark is not one continuous cavern. Its regions are divided by solid rock, deep water, chasms and passages too narrow for ordinary travellers. Two settlements lying close together beneath a surface map may be separated by many days of difficult travel. Elsewhere, an ancient road or navigable river connects communities across considerable distances. Some chambers are scarcely large enough to stand within. Others contain lakes, forests of towering fungi or entire cities beneath ceilings lost in darkness. Worked galleries pass through natural caves, while stairways and bridges reveal the efforts of peoples whose names have been forgotten. Successive inhabitants have repaired, occupied and altered these routes, often without knowing who first constructed them.
Depth influences conditions, but local circumstances matter just as much. Water, ventilation, food and defensible approaches determine where communities can survive. A well-supplied settlement may flourish far underground, while a shallower cavern remains uninhabitable.
Darkness and Sustenance
Much of the Underdark lies in complete darkness. Elsewhere, luminous fungi, strange minerals, living creatures and deliberately maintained lights provide patches of illumination. A distant glow may reveal a settlement, a cultivated cavern or something best approached cautiously. It seldom illuminates the intervening journey. Life gathers where water and nourishment are available. Fungal beds, edible growths, beetle pits and underground fisheries sustain many communities. Great mushroom-like growths provide useful materials, while trade brings timber, grain, cloth and other goods from the surface. Waste is carefully collected in settlements where cultivation depends upon replenishing growing beds. Abundance is uneven. Travellers can pass through miles of barren stone between inhabited caverns. Clear water is not necessarily wholesome, and an unfamiliar growth may be poisonous despite resembling something edible. Local knowledge is therefore valuable, and experienced guides expect to be paid for it.
Peoples and Powers
The peoples of the Underdark are as varied as their surroundings. Drow cities support powerful noble houses, temples and magical traditions. Duergar strongholds command mines, foundries and fortified roads. Deep gnomes, or Svirfneblin, maintain carefully protected settlements, while goblins and other humanoid peoples occupy communities ranging from small farming hamlets to substantial military powers. Other inhabitants are less familiar to surface travellers. Kuo-toa dwell beside underground waters, myconids cultivate their fungal domains, and mind flayers maintain societies whose demands upon other peoples are deeply feared. In the greater depths, ancient powers hold territories that even experienced underground travellers prefer to avoid. Humans and other surface peoples also live below. Some descend willingly as traders, miners, exiles or adventurers. Others are the descendants of captives, refugees or settlers whose former homes have become distant memories.
Ancestry alone offers an uncertain guide to reception. A goblin settlement may welcome peaceful trade while tolerating practices its visitors find abhorrent. A magnificent city may offer comfortable accommodation under laws that afford outsiders little protection. Understanding who governs a place, what they permit and whose interests they defend can matter as much as reaching its gates.
Slavery in the Underdark
Slavery is widespread across many regions of the Underdark, sustaining mines, workshops, households and cultivated caverns. Captives taken in raids pass through established trading networks, while others are born into bondage, their families having lived beneath the earth for generations. Some retain stories of surface homelands; others have never seen daylight and know little beyond the settlements in which they labour. Treatment varies between owners, but even those entrusted with skilled work remain vulnerable to sale, punishment and separation from their families. Not every underground community accepts the practice. Some shelter fugitives or refuse dealings with slavers, while others tolerate the trade provided their own inhabitants are left undisturbed. Escape is difficult in a world where food, safe passages and reliable directions are closely guarded resources. Nevertheless, hidden refuges, quiet acts of resistance and occasional rebellions offer hope—and the arrival of outsiders may present an opportunity that captives have awaited for years.
Roads, Trade and Boundaries
Underground settlements depend upon one another. Food-producing caverns supply mining communities; smiths exchange tools for provisions; porters, guides and merchants carry goods between places unable to provide everything they need. Reliable routes are consequently valuable possessions. Bridges, landing places, wells and narrow approaches may be guarded, taxed or disputed. A toll can support necessary maintenance, enrich a local ruler or simply satisfy the raiders presently occupying the road. News travels with commerce. Arriving merchants bring accounts of shortages, fighting, new passages and missing caravans. Maps are prized, although their owners may deliberately omit protected entrances or profitable discoveries. In many regions, an introduction from a trusted trader opens more doors than an impressive declaration of rank.
The Surface and the Depths
The boundary between the surface and the Underdark has always been crossed. Mines break into older workings, rivers disappear beneath hills, and ancient stairways descend from ruined strongholds. Trade, migration, slavery and warfare have carried people in both directions. For Harmonias, these connections have particular significance. The great humanoid invasion of 329 I.Y. emerged from below, and the subsequent occupation established relationships between surface rulers and underground communities. Reconquest has changed those relationships again, sending survivors, displaced families and armed companies back into the depths. The surface remembers the armies that emerged. Those living underground remember the provisions, recruits, demands and losses that accompanied them.
The Galsitanic Intrusion
The Galsitanic Intrusion disturbed the world beneath Warlderia as profoundly as it altered the lands above. Ancient roads now end against unfamiliar stone. Watercourses have changed direction, established passages have vanished and previously separate cavern systems have become connected. Its consequences continue to unfold. Communities are attempting to restore contact with missing neighbours, recover growing caverns and discover where their surviving roads now lead. Newly opened routes offer opportunities for trade, but also admit predators, raiders and military forces into territories once protected by their isolation. Recent collapses have created further openings, including the Drowned Chasm beneath Mort Swamp. Water and debris descend into passages whose inhabitants may have little understanding of what has happened above them.
The Underdark is being explored anew by people who have lived there all their lives. For adventurers, the Underdark offers ancient treasures, unfamiliar societies and journeys beyond the knowledge of surface authorities. Survival requires preparation, judgement and an appreciation that every road passes through someone—or something—else’s territory.
