From publisher blurb: Explore the Underworld with New York Times Best-Selling author Douglas Niles. New tools, tables, and rules for 5E. The Definitive Guide to Underworld Survival! This tome contains the collected wisdom of legendary dwarven delver Dugmore Dumple. Dugmore takes you through crystalline caverns, fungal jungles and maze-like passages of his home beneath the surface, even skirting the upper regions of Hel itself. Survival in the Underworld is no mean feat, but this massive tome contains all you need to exist and endure, nay, prosper in and profit from the lightless realms below. Dugmore’s sage advice, carefully balanced by seasoned traveler and guide Fin Starling, provides all the tools you require to enhance your experience while exploring the fabled caverns and tunnels below the surface. This book includes an array of modular tools and rules to customize your games. A comprehensive taxonomy of cave types Expanded climbing tools and rules Advice for designing, mapping, and running 3-D environments Modular rules for momentum and chases Rules for mining minerals and exotic ores Streamlined rules for tracking supplies Foraging and hunting rules Detailed segmented spellcasting and combat maneuvers Rules to make tactical combat puzzles Highly modular hazard generators Comprehensive notes on light and darkness A breath-engine for exploration of flooded caverns or spore-choked jungles Rules for hypothermia, hyperthermia, and more exotic afflictions like Shroomitis The lethal hazards of elemental border regions A glimpse at the lightless abyss and the upper regions of Hel Plus, all the tables and tools you need to run an underground exploration campaign.