Dark Water Trap is a mini-adventure that has a single encounter that involves Duergar using darkness and anti-darkvision to get the player to fall into a Pit trap full of water, so that the party will drown. The encounter either works as a standalone (Ie. the Duergar have been causing trouble), or as a part of a larger adventure or dungeon, Duegar or otherwise. Pgs. 26-27

"Imperial Ghoul Outpost" is an iron ghoul lair suitable for four or five 10th-level characters. This adventure can be completed in a single session. When a clan of duergar prospectors unearthed caverns not on the their maps, they were particularly excited about a strange new iron orc they found there. not long after mining began, undead horrors emerged to attack the dwarves. Only one duergar escaped, his mind shattered by the experience. The Ghoul Imperium continues to explore the area, and it has its own plans for the newly discovered one.

After a drow girl goes missing, characters must delve into the depths of the Underdark to bring her back. As they journey through the dark, characters discover not all monsters are monstrous and webs are capable of restraining all manner of creatures; in fact, they can capture magic itself.

When the PCs stumble into the Feywild, they find themselves in the middle of Mithrendain— a glorious eladrin city of grace and beauty. But as the heroes find themselves the target of mysterious attacks, they begin to discover that something rotten lurks in the city’s heart. Sunlight bathes the soaring towers of the eladrin city of Mithrendain. Gentle breezes swirl through wooded parks and along well-kept streets, and in the ancient settlement whos golden hues have seen it named the Autumn City, thousands live in peace and prosperity. For centuries, the fomorian chasms deep beneath the city have stood silent below the great magical seals that closed them in the wanting days of the eladrin empire. Over long years, the folk of Mithrendain have forgotten the dark threats of old, becoming complacent in their tranquility. And so none suspect that corruption lurks at the heart of the city, spreading out from the shadows to taint all it touches. Pgs. 104-128

The Nexus spore is an intriguing Underdark adventure that can be sewn into any subterranean setting. This one-shot production was designed with long campaigns in mind, for when you want to break up the narrative to keep things fresh and interesting. This short adventure is ideal for players of level 5-7, although, much like the length of the adventure, it is easy to adjust. The adventure fits well into a single long session, or 2-3 short sessions. It comes complete with maps, stat blocks, boxed descriptions and a rare magic item.

Ruins of the Grendleroot is a book of ten easy-to-prep and easy-to-run adventures for the fifth edition of the world's most popular fantasy roleplaying game. Designed for characters of 1st to 5th level, these adventures take place in the caverns, chambers, tunnels, and ruins of Blackclaw Mountain, within which lurks a strange otherworldly sentience known as the Grendleroot. Ruins of the Grendleroot focuses on the sense of mystery and wonder that comes from exploring ancient ruins and lost chambers. The central hub of these adventures, Deepdelver's Enclave, is a frontier outpost overlooking the ruined city of Shadowreach, set deep within the mountain. In Deepdelver's Enclave, adventurers and explorers recount tales of their explorations, trade treasure and artifacts, and enjoy their shared love of uncovering the mysteries of the mountain.

Hellmaw Island is a place of legend, a hidden fortress protecting the greatest treasures in the world. Rumour says it is guarded by wicked traps, bizarre and terrifying monsters, and maddening enchantments. Our heroes have been tasked with penetrating this mysterious stronghold, and they will find it to be stranger and more dangerous than anything they have encountered before. Assault on Hellmaw Island is a 5th Edition Dungeons & Dragons adventure for characters of levels 5-10. It will take 4-8 hours to complete.

Tieflings are raiding a dwarven expedition under a shield of magical darkness, but if the PCs can supply the dwarves with giant scarab beetles capable of generating potent bursts of magical light, they might just survive. Unfortunately, they'll need to escort the herd of giant beetles through the Underdark first. A D&D adventure for 3rd-level characters.

Deep beneath the Isle of Dread, in a place forgotten by the world of light, an ancient, unfathomable evil festers. Within the desiccated ruin known as Golsimorga, the debased kopru servants of Demogorgon work foul rites, steeping immature shadow pearls in pits of liquid insanity. None from the world above have yet fathomed what terrors lurk beneath the Isle of Dread, nor what mad scheme roils to profane life deep within the city's gangrenous corpse. "The Lightless Depths" is the sixth chapter of the Savage Tides Adventure Path, a complete campaign consisting of 12 adventures appearing in Dungeon magazine. For additional aid in running this campaign, check out Dragon magazine's monthly "Savage Tidings" articles, a series that helps players and DMs prepare for and expand upon the campaign. Issue #353 of Dragon features ways to improve the PCs' vessel, the Sea Wyvern, as they take their adventures back to the seas. When the PCs journey deep under the Isle of Dread to find the source of the shadow pearls, they discover horrors beyond imagining in a haunted underground city perched on sanity's razored edge. Pgs. 28-66

Part 3 of the Shackled City Adventure Path "Wherein a tribe of the Sea Mother's children suffer for sparing the life of a mad prisoner they probably should have eaten." Synopsis: The adventure begins with an Umber Hulk attack in the middle of the city. The fame gained by assisting during the attack allows them to gain the notice of a representative of Davked Splintershield. The group is asked to rescue Zenith Splintershield from a Kuo-Toan temple in the Underdark. But to find it, they have to visit Crazy Jared to locate an entrance to it. Upon journeying to Crazy Jared's, they fight Hookface's offspring. After more travelling, they are able to descend into the Underdark. Once they find the Kuo-Toan temple, they must fight through many hard challenges, only to realize that Zenith is not a prisoner, but instead is a prophet. Zenith does not go willingly, and so must be captured. Pgs. 28-61

A fast-paced one-shot from the bestselling author of The Secrets of Skyhorn Lighthouse! A shadowy force gathers inside the abandoned halls of Lastwatch Keep. Can the players defeat the drow invaders before they escape to the underworld with sinister intelligence about the surface? Shadows of Lastwatch Keep is a one-shot adventure for four or five 4th-level characters. It takes about 3-4 hours to complete and includes: -A drow strike team desperate to escape the keep’s surprise foe -A new monster, the drow commando -Combat cards for each monster, PC, and special treasure -A beautiful, hand-drawn map by Jake from Beware the Wizard

The most deadly dungeon ever devised! High-level characters brave the unexplored corridors of Deepearth to confront perhaps the most feared adversary in the AD&D game. The second chapter of the Bloodstone Pass saga follows the conclusion of the desperate war against the bandit army. A cold and bitter winter drives the villagers to the edge of starvation, and numerous horrors strike the town of Bloodstone Pass. Join the adventure as the heroes explore the depths of the ancient bloostone mines, now inhabited by fearsome demons. There they hope to uncover the fantastic treasures rumored to exist in the unknown darkness. But deep within the mines, all is not what it seems.... This module uses the new rules from the Dungeoneer's Survival Guide and Wilderness Survival Guide. The adventure also includes optional BATTLESYSTEM scenarios fought entirely underground. These supplementary products are not required to play the adventure, however. TSR 9168

This adventure is written with the intent that it takes place in the subterranean world called the Underdark in the world of Forgotten Realms, although it may be placed in other settings. Within the Underdark, Cyrog's lair can be placed anywhere though it is stated to be thousands of miles east of Gravenhollow. If you are running Out of the Abyss, you may want to have your players see the vision Cyrog Lives! Hail Orcus! (OOTA, 158). Additionally, it is recommended that this adventure be used for a party of 4 to 6 players, level 9 to 12. While merely hinted at through visions in Out of the Abyss, Orcus is roaming the Underdark unchallenged with an army of mind flayers at his disposal. Cyrog, the elder brain of a mind flayer colony in the Underdark has died. The demon lord Orcus has reanimated and taken control of it. The hive of mind flayers is now bent to Orcus's will through Cyrog as he strives to make all life in the multiverse into a vast undead horde under his control. The adventurers are contacted by a patron who gives them a special item (such as brain worms) to suppress their brain waves and make it possible to infiltrate the Cyrog's Lair without immediate detection. The adventurers must defeat or otherwise subdue mind flayers and a few guards, override the elder brain's mechanical defense system, and slay Cyrog.

A band of evil fey, led by a corrupt bralani, has raided an eladrin city and kidnapped several respected elders. The fomorian king claims the rogues don’t act on his behalf, but the eladrin city threatens the fomorians all the same. To prevent war, the PCs travel through the Underdark of the Feywild—a wondrous place filled with the beautiful and the horrifying—in search of the evil fey and their captives. Pgs. 96-101

Rumors of faceless demonic creatures have been steadily rising in the Hillsfar region, and it is said that far below the surface of Faerun, nestled in the bowels of the Underdark, ancient terrors are stirring. The imperiled drow of Szith Morcane have extended an intriguing offer, but can the drow be trusted, and for how long? An eight-hour adventure for 11th-16th level characters.

An unexpected envoy arrives in Sporedome and offers to give aid against the fire giants of Maerimydra, if you are willing to help his people with a small problem. A two-hour adventure for 5th through 10th level characters. Optimized for five 8th level characters.

On a nameless, featureless demi-plane the Tarrasque rages across an all-encompassing nothingness. Last seen on Faerun a century ago during the cataclysm of Odobaz, the battle mage order of the Eldritch Storm sacrificed itself to banish the mighty titan to its demi-plane prison. Now a foul power emerges in the High Ice and nightmare visions of the Tarrasque trampling cities wrack the minds of the living—can your adventurers defeat the Horror Under the Mountain?

The Fate of Faerûn Lies in Shadowy Darkness! Daggerdale is reeling from a sudden series of murderous drow raids. As a grave threat to the entire surface world develops in the war-torn dark elf city of Maerimydra, intrepid heroes must discover its source and destroy it, if they can.

Avalanches are hardly news in Icewind Dale. The frequency to which it is occurring, however, defies logic. What is the cause of this strange phenomenon? What horrors could have unleashed such force of nature with such reckless abandon? Horror Beneath the Frost is a slasher horror adventure set in Icewind Dale, deep within the Reghed Glacier. It features yetis, mind flayers and a boneclaw! The adventure is designed to be easily dropped into: • Any homebrew campaign where avalanches occur. • Icewind Dale: Rime of the Frostmaiden campaign. • Plague of Ancients Seasonal Campaign for the Adventurers League (AL) organized play program. Inside you will find: • A slasher horror adventure optimized for five characters with an average party level (APL) of 8. • Scaling advice for three to seven 5th to 10th level characters. • A printer-friendly version of the adventure. • 4 digital maps importable to Roll20, Foundry VTT and your VTT of choice. Includes gridded, grid-less and printer friendly versions of the maps. • D&D Adventurers League compatible adventure (Dungeon Seed: This Seems Familiar | DC-POA-JL01)

Hunt for a Legendary Treasure! Deep beneath a peaceful valley lies the vault of the legendary drow adventurer Larin Karr. Rumor has it Larin Karr has gone, but his vast treasure acquired from years of plundering hordes in the Underdark still remains. Can you find and loot the impenetrable vault? The Vault of Larin Karr details Quail Valley, its residents and monsters, and the twisting tunnels of the Underdark that stretch beneath it. The Vault of Larin Karr takes PCs from 4th to 9th level, during which time they fight dragons, find a missing statue for a band of renegade elves, save the village of Pembrose from scheming hobgoblins, and explore the Underdark and its many dungeons - including the legendary Vault itself! Contains new monsters and magic items! 2003 ENnie Award Silver Winner: Best Adventure