Book of the Underworld is a sourcebook for 13th Age, the roleplaying game from Pelgrane Press which combines the best elements of both Dungeons & Dragons, Third Edition and Dungeons & Dragons, Fourth Edition to give high action combat, strong narrative ties, and exciting play. It is a guide to the realms below the Dragon Empire. Not the dungeons, but further below, in the realms known as the Underworld, riddled with twisting tunnels and networks of caverns; home to lost seas, lost races, and lost gods; rife with dark secrets and darker kingdoms; and below that? Here can be found the Gnomish school of wizardry, the Arcane Academy in the Burrowdeep Warrens where the graduates swear to never reveal its location upon pain of a curse that changes from graduation year to graduation year and where all sorts of magic is studied away from the eye of the Archmage—even necromancy! Forge, the Dwarven City of Memorials to the lost ancient civilisation of Underhome which stretched across the Underworld and which the Dwarven King still claims as his—along with much of the Underworld. Drowfort, a magnificently dark fortress sphere suspended by webs amidst a circular cavern, where factions of the Drow dedicated to the Elf Queen, She Who Spins, and both without ever revealing their allegiances co-operate to impose martial law on the Underworld. The Caverns of Lost Time in the Hollow Realm where whole regions of both the Overworld of the Dragon Empire and the Underworld, as well those of previous and lost Ages have been swallowed and preserved. Below that, glimpses of Underkrakens might be caught, seas of chaos writhe and surge, gods repose in their great catacombs, and something stranger still might be found—possibly the great architect of the Living Dungeons which burrow up the Underworld to the Overworld… And he has a beard, wears glasses and Hawaiian shirts, and speaks with a Midwestern accent, that would not be the strangest thing in Book of the Underworld.
The Book of the Underworld is a slim volume of ideas, places, monsters, advice, lists of thirteen things, and more, all designed to take a Game Master’s campaign even deeper underground. It is by no means a definitive guide to the Underworld, but it contains more than enough content and ideas to fuel multiple campaigns. Some locations its fleshes out in detail, such as Forge, Dwarven City of Memorials with its multiple districts and NPCs, or Web City, the stalactite city home to two cults—the Cult of She Who Spins in Darkness and the Cult of He Who Weaves With Joy—and innumerable spiders and drow, a fantasy ’noir setting strung across the ceiling of a great cavern, whereas locations such as the Dark Temples where the darkest of gods hide from the light and the Salt Mines of the Manticore, a sprawling salt mine used in ages past as a prison with one entrance pit in manticores were free to feed on the salty inmates, get just a paragraph or two. Whilst the former are more ready to play and easier for the Game Master to bring to the table, the other locations are more ready for her input and development of her own ideas and content.
The Book of the Underworld does require access to a number of supplements for 13th Age. In addition to the core rulebook, the Game Master will need the 13th Age Bestiary, 13th Age Bestiary 2, and 13 True Ways, whilst 13th Age Glorantha, Book of Ages, Book of Demons, and others will all be useful. It divides the Underworld into three layers. These are in descending order of depth, the Underland, the Hollow Realm, and the Deeps, which correspond roughly to the three tiers of play in 13th Age—Adventurer, Champion, and Epic. As with other supplements for 13th Age, it ties in the thirteen Icons and their relationships with the Underworld, which of course can be used to spur the Player Characters into descending below either on their behalf or to stop their plans. It throws in too, several fallen, vanished, and refused Icons, such as the Explorer from the Book of Ages or the Gold King—a former Dwarf King turned undead from 13th Age Bestiary 2. It introduces the Calling, the alien desire which subverts an existing icon relationship and compels an adventurer to travel further into the Underworld…
The supplement also discusses the roles which the underworld can take in a campaign, from a source of evil or monsters to a realm which is either hidden, prosaic, or weird, if not a mixture of all three, as well as using as the setting for a quick delve or a longer sojourn across an entire tier of play. Rather than suggesting that the Game Master map out each and every tunnel or cavern, it gives guidelines on how to use travel montages and include the players’ input and descriptions to detail and enhance the various locations their characters come across to make it interesting and involving, but shies away from focusing upon the day-to-day tracking of resources such as food, water, and sources of light. It adds a few treasures, such as the Drow Poesy, made of flowers plucked from Hell and the Bezoar of the Caves, former magical items belonging to adventurers chewed up and spat out by carnivorous caves, as well as numerous new monsters, but the latter tend to be specific to their locations.
The two races to receive the most attention in Book of the Underworld are the Dwarves and the Drow. Both are well handled and nuanced, but the interpretations of the Drow are the more interesting, if only because they are not portrayed as the out and out villains they often are in other settings, but rather accorded multiple interpretations which the Game Master can pick and choose from. Also known as the Silver Folk, they are primarily divided between those loyal to the Elf Queen and those loyal to the Cult of She Who Spins in Darkness. The realm of the Silverfolk lies below and extends beyond the Queen’s Wood. Numerous options for obtaining access are given, such as via ancient fairy mounds or sigils spun by spiders, and the Silver Folk might be divided into family clans of extreme specialists, whether that is of duellists, torturers, mushroom farmers, spider herders, artists who paint living portraits, and more; operate as the Elf Queen’s secret police; be exiles from the Queen’s Wood above; or reside in cavern dens as drug-addled fiends and hedonists, or laboratories where alchemy is practised as an art. The other Drow locations detailed in the Book of the Underworld, Drowfort and Web City, are located below in the Hollow Realm and are likewise accorded options of their own from which the Game Master can choose—as with much of the supplement.
Elsewhere, the Book of the Underworld provides lists of ways to get into the Underworld—including via the Abyss for Player Characters who want to make their delvings all the more challenging and for the Game Master who wants to make use of the Book of Demons, an explanation of how druidic earthworks work—above and below ground, the Grand Dismal Swamp—complete with Troglodytes and Fungaloid monsters, and not one, but four kingdoms of the Mechanical Sun! There really is a lot for the Game Master to play with in the pages of the Book of the Underworld. Plus it need not be just for 13th Age. The ideas and settings in this supplement would work equally as well in a lot of other fantasy roleplaying games too.
Physically, the Book of the Underworld is well written, but not always well illustrated as the artwork varies widely. It presents a wealth of ideas and options as well as particular locations, some already developed, others awaiting development upon the part of the Game Master, that she can bring to her campaign. Or indeed, actually turn into a campaign! The Book of the Underworld literally adds depth to 13th Age and content that a Game Master can mine for scenario after scenario and campaign after campaign.