Ten underground adventures for the fifth edition of the world's most popular fantasy roleplaying game, set within a ruin-filled mountain torn apart by the mysterious Grendleroot. Ruins of the Grendleroot is a book of ten short 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 the mountain known as Blackclaw, within which lurks the Grendleroot--a strange and otherworldly sentience. Across these ten adventures, your characters will cure the corruption of an old tower destined to bring daylight to the cavern of Shadowreach; rescue a lost child who answers the call of a dying god; seek out the source of a plague of gnome zombies; travel to the Forest of Iron to stop the priest who would destroy the Grendleroot-and the entire mountain surrounding it; protect Deepdelver's Enclave from marauding warbands of orcs and hobgoblins; find the beast lurking in abolethic ruins that promises salvation in return for fresh meat; seal up a damaged cell in a forgotten monastery, which contains a being so dangerous that even its thoughts can kill; save a war hero from the elven assassins who hunt her down; discover the secret to quieting the restless Grendleroot from a slumbering vampire archmage; and travel to the Black Cathedral, discover the origin of the mysterious Caretakers, and stop a mage attempting to capture the power of the Grendleroot for herself. Ruins of the Grendleroot focuses on the sense of mystery and wonder that comes from exploring ancient ruins. 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. These ten adventures can be run independently as single-session games of roughly two to four hours each, or they can be tied together as part of a larger campaign. Five of the adventures can be combined together into a five-session mini campaign that focuses on the strange consciousness lying at the center of the mysterious mountain. Each of these ten adventures is designed to get you up and running quickly and to help you integrate them into your own campaign. If you're familiar with the format of the book Sly Flourish's Fantastic Adventures and the concepts in the book Return of the Lazy Dungeon Master, the setup of these adventures will be familiar to you. Even if you aren't, you'll find the design of these adventures intuitive and straightforward. In this book, you'll find inspirational artwork, beautiful maps, fantastic locations, short readable summaries of places and events, evocative keywords to spark your own imagination, flexible read-aloud text, and piles of ideas to fuel your own stories.