Dungeon of the Mad Mage

There are two kinds of Dungeons.

Type A: Dungeons that make sense.  These dungeons take into account the function of the structure, as well as the ecology of the denizens.  There will be a theme to your foes: If it’s a goblin cave, you will mostly fight goblins, their pet wolves, and their hobgoblin bosses.  The layout will be functional: You’ll find sleeping areas, kitchens, storage rooms, and so on.  Traps will be minimal and will only protect valuable areas, such as the room where bandits store their loot.  If you’re exploring a Type A dungeon, you may not even have to clear out the entire thing.  A sensible hideout is easy to navigate, so you might break in at a point closest to your goal, clear out a few rooms, grab your MacGuffin, and head back out.  Type A dungeons are efficient and realistic, but potentially boring.

Type B: Kitchen Sink dungeons.  You never know what to expect in a Type B dungeon.  You could clear out a room full of manticores, then open the next door, and find yourself facing a room full of orcs.  Then you turn a corner and come face-to-face with a bugbear, a vampire, and a harpy.  You may find yourself wondering how these monsters get along, what keeps certain ones in their rooms, and who feeds them.  You’ll encounter traps that are designed to kill explorers, rather than to protect treasure.  You’ll complete complicated puzzles just to open doors to what look like high-traffic pathways.  Do the orcs that live here have to solve this “pour the right amount of water into the basin” puzzle every time they visit the kitchen?  Type B dungeons are less believable, but also less predictable, which makes them exciting.

Some Type B dungeons actually do have an explanation.  (Note, this paragraph contains possible spoilers for classic modules.)  The Tomb of Horrors is full of crazy traps, because the demilich Acererak likes collecting the souls of dead adventurers.  White Plume Mountain houses an unlikely menagerie of monsters, but the entire dungeon turns out to be a test of heroism, designed by an evil mage who requires a true hero for a blood sacrifice.   Dead in Thay has the Doomvault, a bizarre dungeon designed for magical experiments... or something; that module has never made sense to me.

Many dungeons are a mix of A and B.  The Temple of Elemental Evil is a pretty good balance of the two.  Each of the elemental-themed areas has their own reasonable ecology, but having it all so close together makes the dungeon as a whole seem pretty random.  I would have to say that the best dungeons are the ones that can straddle that line, by giving you a unexpected encounters while maintaining a consistent theme.

Dungeon of the Mad Mage is a bit of both.  The Undermountain’s dungeons were obviously designed by a lunatic (hence the title), but there is some logic to the denizens.  Different areas of the dungeon have been taken over by certain organizations or monsters, so there’s a lot of variety, but it’s not like each room has a completely random monster.  Given the popularity of this dungeon, the party will find a lot of the early areas have already been picked clean by previous adventurers, which is a realistic touch.

The ecology of each level usually makes perfect sense, but moving from one level to the next can feel like an entirely different module.  Why do the monsters and factions respect the concept of "dungeon level"?  All that divides this level from the one before it is a slanted tunnel, why do the kobolds suddenly get replaced with kuo-toa?  

A few levels down, you start finding unusual environments for a cave: cities, enchanted forests, floating castles, and so on.  A couple of levels are actually 5e conversions of older modules.  Sometimes you will often find keys on one level that unlock doors on another, so there is some connection between levels.  Occasionally someone will give you a side quest, and you’ll find the MacGuffin three levels later. 

This dungeon is big.  Probably the largest single dungeon published for 5e, at least by WOTC.  It goes down 23 levels, and even has a few hallways that lead nowhere, in case you want to add your own expansions.  The 320-page book devotes 289 pages to the dungeon, making it one of the largest dungeon-to-lore ratios I’ve seen.  

I honestly can’t imagine taking a party through the entire thing.  I think they would develop “dungeon fatigue” after a while (and a vitamin D deficiency).   The good news is that it’s designed so you can leave and come back, with lots of teleportation portals for quicker travel.  So some parties might keep returning to the Undermountain between other adventures.

While the book does contain a few plot hooks, it doesn’t need them.  This is the infamous dungeon beneath the Yawning Portal, and adventurers need no other reason to delve it than “because it’s there.”  But once the party starts exploring the passages, they will find other small quests to keep them busy.  So it’s not just “let’s kill all the monsters and find all the treasure”, though it certainly can be if that’s all the party wants.

Dungeon of the Mad Mage is a great companion to Waterdeep: Dragon Heist, but you don’t need either one to enjoy the other.  There is no strong plot connection between the two.  Grab Waterdeep: Dragon Heist if you want the lore of the area, and grab Dungeon of the Mad Mage if you just want a big ol’ dungeon.