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.

The Underdark is a subterranean wonderland, a vast and twisted labyrinth where fear reigns. It is the home of horrific monsters that have never seen the light of day. It is here that the dark elf Gromph Baenre, Archmage of Menzoberranzan, casts a foul spell meant to ignite a magical energy that suffuses the Underdark and tears open portals to the demonic Abyss. What steps through surprises even him, and from that moment on, the insanity that pervades the Underdark escalates and threatens to shake the Forgotten Realms to its foundations. Stop the madness before it consumes you! Note for DMs: This adventure is not for the faint of hearted, to run or to play. The module starts with 10 NPCs traveling with the party through the grueling Underdark. This number can grow. The encounters within the book are often incredibly deadly for the characters that would be going through it. This is because the module expects them to run or talk their way through the events, or, in some cases, the module expects them to lose. If your players aren't the kind of party to run, talk, or surrender, do not get this adventure. The module almost requires that you use milestone leveling because the experience provided does not commonly get players to the levels they should be once they get to certain milestones in the story (7th when they leave the underdark, 15th when they face the demon lords.) Good luck and happy questing.

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?

Eons ago, the demon lord Shomarrah defamed Lolth the Spider Queen, condemning herself into the cursed life of a massive purple worm. Now Shomarrah's desecrated body serves as a drow fortress, guarded by a mad sorcerer and his team of driders. What deeper evils lie within? "The Fasting Worm at the Spider Feast" is a Dungeons and Dragons 5th Editionmodule for a party of 3-5 players at level 8. This one-shot module is perfect for introducing your party to the Underdark and drow society, featuring a dungeon dive through a demon lord's snake-like carcass. Clerics in the party, upon completing the adventure, will be able to obtain access to the Feast domain. Details are provided at the end of the module

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.

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. Then, the heroes journeyed to the orc’s former settlement beneath Wyvern Tor and found the source of the orc’s sardonyx and the umber hulk that drove the orcs out. Now, the party has to go deeper to deal with the terror from the Underdark that caused all of this excitement.

The Underdark holds many secrets. A series of earthquakes and eruptions have rocked a normally placid land. Strange creatures sighted in the dark of night raise fears across the already disturbed countryside. As tales of a lost race that once warred with the drow begin to surface, only the boldest adventurers dare to descend into the shadowy darkness.

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!

A special underworld encounter from DUNGEON Adventures! The toll may be higher than you can afford... To travel further into the Underdark the party must cross a bridge spanning a deep chasm. But to cross, they must pay the toll, or risk another route. Pgs. 47-54

Side-Trek adventure When your PCs gain access to the teleport spell, their whole world changes. That simple spell opens up instantaneous, long-distance travel. No more long overland journeys or dangerous retreats through hostile territory. All it takes is clasped hands and a word from the wizard, and poof! The PCs are where they want to go. Except that it isn’t that simple, because teleport isn’t foolproof. The off-target teleports are a matter of scattering your PCs someplace else on the map and forcing them to get their bearings and make the long overland journey anyway. But this Side Trek focuses on the really intriguing column on the teleport chart: “similar area.”

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.

Undermountain: The Caverns of the Many-Legged is an adventure detailing a hidden mini-level for Dungeon of the Mad Mage for characters of levels 12-13. It uses some of the story and lore of that book, but it can be incorporated or dropped into any setting or homebrew campaign. In a hidden part of Undermountain, former slaves feed their fat, monstrous queen who is fixated on revenge. A broken drow house has finally found a place to call home – only to become abominations. And a massive beast slithers, hunting for anything to satiate its hunger and quell its madness. Welcome to the Caverns of the Many-Legged. Which side, if any, will adventurers choose as they explore this hidden mini-level for Dungeon of the Mad Mage? In this adventure, you will find: a mini-level that can be easily incorporated into Dungeon of the Mad Mage a vivid cast of unique monsters and NPCs, including chitine warriors, a choldrith queen, a spellcasting draegloth, a mad yuan-ti anathema, and others (stat blocks provided for all creatures not in the Monster Manual) locations that could be used or adapted elsewhere, such as a chitine colony and a drider-controlled drow fortress a combination of roleplay, exploration, and combat encounters

A strange journey through a living cavern. A request for help to rescue a mining crew leads a group of adventurers into a cave that has seemingly come to life, gripped by a melancholy wave of sadness and memory. In dark caverns where mushrooms walk, vines dance, walls watch, and stones speak, will your band of adventurers become heroes? Or will they be lost within the Mines of Memory? Mines of Memory is a short, 2-3 hour adventure for characters of levels 1-3. It is a delve into a cavern system that has become a Psychic Resonance environment, awakening the caves themselves. PCs will enter to rescue the miners, find the source of the mine’s awakening, and bring peace to a noble creature trapped in its own nightmare.

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.

The land of Felora is a stable pedocracy off the Feso Seaway. Generally considered a safe place to live because of a low humanoid population and a large defensive wall that rings the country. The same cannot be said for the area to the west known as the Wildlands. Once a thriving human land the area was taken over in humanoid raids a century and a half ago. With the aggressions against the wall lessening the Council of Wisdom is organizing groups to go in and explore the land for possible "taming". Potential explorers will be paired off with non-combatant survey teams. Are you new adventurers ready for a job? Played at Epic Nerd Camp '17!

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.

Waves of supernatural darkness sweep over the subterranean city of Stoneholme, quenching lights and bringing with it foul creatures of shadow. After heroically defending a group of dwarven children being ravaged by a group of these shadow beings, the PCs are approached by Shtawn Deppenkhut -one of the king's own advisers- and are offered the task of finding the source of the darkness that threatens the city. The PCs investigation takes them through the Underworld to hidden caverns, where demon worshiping priests offer living sacrifices in an attempt to plunge Stoneholme into everlasting darkness, a first step in destroying the hated city once and for all, but as it turns out the priests aren't the only ones behind this unfolding plan to destroy Stoneholme. Dark Days in Stoneholme is ideally suited for a group of dwarven adventurers. It is recommended that you have access to the Stoneholme section of the Rise of the Drow revised & expanded edition (2014) but it is not necessary to run the adventure. Also available for Pathfinder. Published by AAW Games.

A mind flayer has called for a massive conference of monsters in the Underdark beneath Hillsfar. Trolls, umber hulks, demons, and more have answered the illithid's call. To infiltrate this gruesome menagerie, you must embrace the monster within yourself.

When her father goes missing, a young adventurer has no other choice than to gather her friends and head for the city of Loudwater. Soon after she gets swept away in an obscure design threatening to drag the entire region into chaos and war. At the heart of this mystery, lies not only her father, but the long-forgotten history of her once-despised family and a primordial beast influencing events from the shadows, moving her family like pieces on a chess board. Visit www.perfumersdaughter.com for more information. You can also address me directly on The Perfumer's Daughter Q&A on Facebook. All battlemaps and dungeons are free to download for use in digital platforms (such as roll20) on the aforementioned site.

An escaped duergar slave stumbles into the village of Elventree. With her she brings a malady that grips the small settlement in a bout of madness that seems unshakable. Can you find the source of the madness and save yourself and the village’s inhabitants? A four-hour adventure for 5th-10th level characters.