Of all the inhospitable domains in the RAVENLOFT@ campaign world, Bluetspur is the cruelest and most gruesome. Nothing grows in the endless night, and lightning periodically falls like rain. The only place to escape those storms is inside the mind flayers' complex under Mt. Makab, but that is the last place where any sane person would want to go. The High Master Illithid has been hatching black plots by hatching vampiric mind flayers in his laboratories! His prodigies are horribly insane, but if he can complete his plans, he will achieve a new level of dark immortality. A pair of heroes has stolen the key to his success, but they have paid a heavy price for their bravery and are in desperate need of aid unlooked for. Meanwhile, the Lord of the Realm watches over the proceedings and plays havoc with the wits of both sides, sapping strength and will with all-powerful thoughts of darkness. A party of adventurers will need all of their skills to escape this black domain without the loss of life, power, or sanity! Enter now the perpetual twilight realm of Bluetspur, home to mind flayers, a land of relentless nightmares. There's no rest for the wicked or the good in this domain. Once caught within the borders of this desolate land, the characters must complete their mission without delay or lose their minds and become slaves of the Lord of Bluetspur. TSR 9264, from 1992

As a member of a bold party of adventurers, you and your associates have trekked far into what seems to be a whole underworld of subterranean tunnels -- arteries connecting endless caves and caverns which honeycomb the foundations of the lands beneath the sun. Your expedition has dogged the heels of the Dark Elves who caused great woe and then fled underground. This module can be played alone, as the conclusion to module D1 & D2: "Descent into the Depths of the Earth," or as the third module in a series that forms a special extended adventure (G1-G3: "Against the Giants"; D1-D2: "Descent into the Depths"; and Q1: "Queen of the Demonweb Pits"). TSR 9021

The kuo-toa are a piscine race with a psychic affliction that makes them behave erratically and invent gods when feeling threatened. That same affliction gives them the power to bring those gods to life. Blibdoolpoolp is the most widely worshipped, and thus most powerful, of their gods. Blibdoolpoolp views the kuo-toa as her children despite having been born after them. Like all good mothers, she nurtures and protects. One of her chief concerns is understanding the kuo-toa’s psychic affliction, which causes them to undermine themselves whenever they strive for greatness. She discovers that a corrupted elder brain deep in the Underdark has a connection to the race; though the connection gives them psychic powers, it also turns them into powerless thralls, explaining their self destructive behaviors. Constrained by the same leash on her children, Blibdoolpoolp seeks adventurers to destroy the elder brain. Its death would free the kuo-toa, but potentially at great cost: if the kuo-toa lose their powers, will Blibdoolpoolp die?

A missing mage... A ruthless band of kidnappers... A sinister conspiracy... Night Below, the first epic campaign adventure for the AD&D game, is designed to take the player characters from 1st level to 10th level and beyond. The PCs start as beginning adventures on a routine courier mission who soon become drawn into combating a sinister plot that menaces the pleasant land of Haranshire.

A dwarven expedition has stopped in Mulmaster for much-needed supplies. Furgis Boltsmelter, their founder and leader, is looking for some “no questions asked” protection for the duration of his stay in the city. Whatever he is trying to protect may not stay hidden for long. Can you keep his secret treasure out of the wrong hands? A four-hour adventure for 1st-4th level characters.

The Baronies of Erlkazar, once a prosperous region of pastoral tranquility, is now a land of nightmares and dread. Bandit armies plague the region, terrorizing the populace and surrounding countries of Calimshan, Tethyr, Amn, and Turmish. Though these threats are terrifying enough, it is nothing compared to what awaits the people of Erlkazar at night. In caves, tombs, and subterranean communities beneath the seemingly pastoral villages of Erlkazar live the secretive Night Barony. Ruled by the vampire Saestra and her legions of darkness, these monstrous denizens of the Five Baronies are the real power in the region. The country’s only hope of liberation is you.

The Ghost Tribe of Orcs were driven from their home under Wyvern Tor by some terrible evil. They marched to Phandalin and attacked, only to be defeated. Now the heroes will go beneath Wyvern Tor to discover the terror that chased out the orcs and perhaps find the source of the orc’ssardonyx. Journey to Beneath Wyvern Tor is the third of four parts in the After Lost Mine series. It will play out the journey to the orc’s former cave settlement and then into the darkness beneath. Part IV will have the party deal with the terror from the Underdark that drove out the orcs.

Are your player's going fishing in the Underdark? Booked a ride with the Kua Toa Travel Agency? Taking a cruise on the Darklake? Well then Journey Through the Center of the Underdark 2 - The Darklake Strikes Back is just what the Leemooggoogon ordered! Like the first Journey, The Darklake Strikes Back contains several encounters designed with Out of the Abyss traveling days in mind, but easily inserted into any 5th Edition Dungeons & Dragons Underdark setting. Unlike the first Journey, The Darklake Strikes Back has a mid sized three level dynamically defended dungeon, complete with a dragon at the bottom! This complex is right at home on the Darklake but could also readily be inserted into your Tyranny of Dragons campaign as well. Written for a party of characters levels 4-6 with notes included for adjusting encounter difficulties for lower or higher level groups Journey Through the Center of the Underdark 2 - The Darklake Strikes Back should provide 6-10 hours of gameplay excitement!

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.

The Red Plumes have increased patrols in the region surrounding Hillsfar, and a string of disappearances has followed in their wake. Naturally, this has roused the suspicion of the factions. Join your factions and find out the truth behind the missing farmers. A four-hour adventure for 1st-4th level characters.

In Prisoners of the Drow, a band of adventurers storm a drow outpost, confront the drow mage in charge of it, and rescue prisoners held within. The heroes must bypass traps and devious defenses to reach their goal and accomplish their mission. The adventure is designed for a party of five adventurers between levels nine and twelve. It features: Encounters by Level - Varying types and quantities of creatures are suggested based on the party's actual level, allowing each encounter to present the appropriate challenge to the party. Encounter Notes - Suggestions for how to run combats are provided for game masters who place an emphasis on engaging, tactical battles. Inciting Action - Suggestions for ways to present the adventure to players are provided. Ease of Use - The format and style of the document allows the game master to find information quickly while running the game at the table. Detailed Maps - What's an adventure without maps? Not much else to say here. This adventure is designed as the first in a two-part series. The second adventure Into the City of Spiders takes the adventurers into a drow compound far from the surface. https://www.drivethrurpg.com/product/247674/Into-the-City-of-Spiders

Expand your game with this collection of 56 NPCs of various Challenge Ratings, thirteen of which include maps and details of their lairs. Add these NPCs as a side-quest, a main villain, a one-shot, a bounty for easy money, or however else you wish. Written by some of the best-selling authors on the Dungeon Masters Guild and outstanding podcasters, each NPC includes an image, a backstory, motives, flaws, and a stat block. Some even include new magic items!

Troubles simply mushroom in the Underdark. The alchemist would like some fungus and spores, but no one wants to get them. Perhaps you could help. The adventure begins with the party finding a caravan. In addition to being able to trade with these NPCs, the party also can be hired by an alchemist to bring bag some red fungus and some Myconid spores from underground. Underground, the party will have a chance to interact with friendly Myconids and venture through a large labyrinth of passages (this labyrinth isn't mapped and is dealt with through storytelling, random encounters, and roleplay). The adventure culminates in a battle between the Myconids and Flinds, and the players can participate. Pgs. 4-12

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

A 20-page adventure for OSE Save the wizard! A sunken cathedral on a quiet mountain lake hides a long forgotten temple to Mathanoga, God of Knowledge and wizardry. Abandoned by Man for centuries , but protected by the legend of man-eating fishmen lurking in it. Or until a few weeks ago the young wizad Elric embarked on its expedition. With help from the accademy of Greykeep he found the temple and began to explore it, hoping to uncover its ancient magical secrets. Now the wizard is missing and the accademy has put a bounty on its head: its weight in silver to whoever will find him and bring him home alive and well. Find magical secrets! Deep inside the temple are stashed many magical items, all sacred to the fishmen dwelling there, all worth dying for. Save Elric and the treasures will be yours! The Sunken Temple is an expert level Old School Essentials adventure for a party of 1-4 players. Perfect for a one shot or a random encounter in an hex crawl.

What elder evils lurk in the depths of the freezing mountain ruins? Find out in The Stoneheart Ruin! The adventure features: An adventure set in a desolate, wintry mountain landscape. 16 pages full of intrigue and mystery, containing full color maps, plus 2 unique monster stat blocks. Provides a great introduction to Mind Flayer lore and mythos for Tier 1 players. Can easily be set in the Spine of the World for use in Rime of the Frostmaiden. Let your characters test their mettle as they climb and face the ancient dangers lurking in the cracks of The Stoneheart Ruin! “I have no explanation for any of these finds. We heard disturbing noises coming from further within the mountain; thunderous and growling.” Excerpt from a pamphlet, signed: “Koralia Meadring, Anthropologist Extraordinaire” Koralia needs you to investigate her most recent discovery: a ruined cavern deep in the mountains. Her small team of academics did a cursory walk-through and think they've found a big breakthrough! However, they left in a hurry after being frightened by the horrors they heard coming from deeper in the mountain. They escaped and found one of their team was missing - a goliath named Marek. You must climb the mountains and locate the ruin, make certain that it is safe for study by Koralia’s team, and if possible, find and rescue Marek, whose fate is uncertain. Made during the November 2020 RPG Writer's Workshop.

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?

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.

She ran. Where to or for how long, she really couldn't say. The little flame of her oil lamp sputtered and went out a few times. She'd snap her fingers and make the wick flare to life, but she may as well have ran blind. The hallways were pitch black with soot and choked with smoke, every turn was a guess and every corridor a gamble. Unnatural screams echoed from every direction. Left, right, left again, was this the south or north end of the labyrinth? She had no idea. The next turn brought her face to face with a doorway completely consumed in blue fire. The room beyond was so bright she had to look through her fingers at it. A shadow covered her, a shape in the doorway: a hulking creature with a wolf-shaped muzzle and enormous pincers for hands, wreathed in the same blue flames. The screams were getting closer behind her, too. They had her cornered, again. The demon slammed its shoulders through the narrow opening, splintering the wood and stone. She dropped the lantern and let the wand in her sleeve fall into her waiting hand. With a word of power and a gesture, she appeared in the familiar bedroom: stuffy and reeking of wood smoke. She'd have to try again tomorrow, if she could remember. During an exploration on the sixth level of Undermountain, a strange invisible creature leads to a series of collapsed chambers that hide a forgotten secret and one of the most devastating forces known to the multiverse. Marambra Nyghtsteel, the forgotten apprentice of Halaster Blackcloak, has been locked away for an age deep within Undermountain. What point and purpose her forced seclusion has, only Blackcloak may know. When a spell consuming blue fire, known as The Spellplague is trapped within the chambers, a series of events have left Marambra, lost in her madness, struggling to survive.

Gyldrith the Great is coming, and she is not happy. How long have you been down in these caves? Days? Weeks? More? Time is hard to track this far underground. And so much has happened since you descended into the tunnels beneath Dhonin’s Lookout. Now, you stand guard at the Great Gate of Naakrasad. Exhausted from your past battles, and your narrow escape from the cat and mouse games of the ancient deep dragon, Gyldrith. You can hear the hoots and hollers of her horde of bloodthirsty minions just beyond the city walls. A battle is coming, a battle against great odds. A battle that will test your mettle like none before. And you wonder if you are up to the task. A massive battle ranging across the small city of Naakrasad in the Underdark. Giant map of the city of Naakrasad with close-up details of the major battle sites in the adventure. Several new monsters, including the vicious Half-Ogre Hound Master and his deadly Hell Hound pets. Unnumbered maps, including the entire city of Naakrasad, to use in your favorite VTT.