Dungeon of the Mad Mage takes place almost entirely in Undermountain, a vast dungeon complex under the city of Waterdeep. Undermountain has shown up a few times in past editions, being the subject of a couple boxed sets as well as a couple previous hardcover adventures.

What It Is

This book is entirely one bigass dungeon crawl. Undermountain is effectively a giant super dungeon that can fill a campaign running from levels 5 to 20. Unlike previous versions of Undermountain, this book focuses on “going deep rather than wide”. It highlights twenty-three different layers of the dungeon, including several that have been detailed before. Unlike the titular dungeon in Tomb of Annihilation, the focus here is exploration, delving into weird dungeon levels and interacting with the inhabitants rather than wacky funhouse traps and puzzle chambers. There are weird magical effects, odd chambers, and a LOT more monsters but fewer death traps.

The book is 320-pages, making it slightly larger than the Player’s Handbook and Dungeon Master’s Guide. As mentioned, there are twenty-three dungeon layers with over 650 individually chambers and rooms, with many additional sub-chambers. There are also five pages on the city of Skullport and twelve monster statblocks, a half-dozen of which are reprints.

Dungeon Levels

Here’s a quick summary of the various levels of the dungeon.

Level 1 and 2: Big Dungeons

Level 3: Hobgoblin Settlement

Level 4: Mini Underdark

Level 5: Subterranean Forest

Level 6: Dwarven Ruins

Level 7: Stone Giant Cavern

Level 8: Swamp Cave

Level 9: Magical Academy

Level 10: Drow Enclave

Level 11: Besieged Troglodyte Warren

Level 12: Minotaur Maze

Level 13: Junkyard/ Workshop

Level 14: Fire Giant Forge

Level 15: Funhouse/ Obstacle Course

Level 16: Githyanki Incursion

Level 17: Mind Flayer Bastion

Level 18: Evil Cultists

Level 19: Oozes with Spelljammer ship

Level 20: Lich Lair

Level 21: Planar Mine

Level 22: Rando Fortress

Level 23: Evil Archmage Lair

More or less… Some are harder to condense to a single descriptor. There’s often more than a few twists and surprises. What I take away from a level might not be the defining feature to someone else.

The Good

As mentioned, Undermountain has been detailed before, but typically focusing on the top three levels which were (implausibly) big, sprawling horizontal dungeons. The maps of these layers here are much smaller, covering just half of those levels (or probably a quarter in the case of the third level) but keep the same general layout. There’s a few changes suggesting the passage of time, such as a few collapsed passages. On each map, passages continue off the map, implying other chambers simply aren’t covered here. This means the dungeon rooms from past books didn’t vanish, and still exist: allowing the Dungeon Master to expand the dungeon if the players want to continue exploring, updating what came before if they have past books or even adding new chambers from their own imagination. I expect the DMs Guild to fill out a few of those areas in short order.)

The book begins with a list of dungeon levels and the appropriate character level to delve in them. Also in the introduction is sample xp awards for bypassing traps and environmental hazards. Handy. Meanwhile, each chapter begins by outlining the inhabitants and major conflicts of that layer. This helps greatly for prep and even reminds you to read certain sections of the Monster Manual.

There are a few quests at the start of the book to get player characters going, and more provided later in to keep them delving. A few additional quests are included in later dungeon levels.

There’s a wide variety of dungeon levels, including artificial catacombs, caverns, and even a forest and a swamp. While this is odd, the whole complex is explicitly managed/ curated by a mad archmage, making the “a wizard did it” excuse less handwavy. The book repeatedly mentions Halastar making changes to accomodate inhabitants or bringing in new creatures to reside in a level then customizing it for their needs.

This variety males the adventure very easy to steal from, as you can just pull out a dungeon level for one to three game sessions. If you need an Underdark cavern or former dwarven stronghold hen you can easily steal one. Especially with the general absence of an overarching plot.

Despite the ease of theft, layers are also not entirely stand-alone, as factions on neighbouring floors can interact, trying to fight enemies or spread their influence or in a sequential order. This encourages you to keep delvling, or provides the opportunity for a sequel if lifting a dungeon level.

Meanwhile, Halaster is a continual presence throughout the dungeon. He’s not some mysterious force that doesn’t appear until the climax, suddenly becoming involved in the story. Instead, Halaster continually reminded delivers he is around and a menace, with statues and illusions of himself or message spells taunting the PCs. I quite like this, as the players are always reminded the Big Bad is present and aware of them. It allows an opportunity to interact with Halaster before the final fight without directly putting him at risk of being killed too soon.

The inclusion of various mirror gates allow some fast transport between levels. But not always directly where you want. They require some experimentation and exploration, like so much of the rest of the dungeon. For a campaign set entirely in the dungeon this is very useful, as the party will likely make repeated trips to the surface over the course of their adventure. A campaign like this really needs regular breaks with a trip to the city to avoid burnout, as well as sell found treasure.

The dungeon is presented as changing and not a static location where the PCs are the first adventurers to arrive. There are repeated mentions of past adventuring companies, who died or were trapped while exploring (some of which could serve as replacement PCs or hirelings). It’s odd that more traps haven’t been pre-triggered or treasure looted, but that’s easy enough to explain with Halaster and other denizens resetting traps. This reminds the players that their PCs aren’t somehow the first to reach certain levels in the highly famous dungeon, and makes the dungeon feel like a living world. Similarly, the end of each chapter gives some advice for how that dungeon level might change as a result of the PC’s actions. Both these really make the dungeon feel like it is a living, breathing adventure site and that the player’s choices and decisions have an impact.

As mentioned, the few monsters not from the Monster Manual are reprinted. Most of the time. Space was clearly at a premium as a few monsters didn’t make the cut, such as the drow house captain. In these instances, rather than lock-in a monster not in a core book, the description suggests an alternative that is in the MM, to be used if the Dungeon Master lacks Tome of Foes. I like that expensive accessories are not mandated.

The Bad

Despite beginning at the Yawning Portal inn and tavern, there is no map for that locatiob, and it only receives a quarter page description. It receives more fleshing out in Tales From the Yawning Portal, an adventure that does not actually take place there. This would alos have been a better place for the fun image of the tavern and its residents that appeared at the start in Waterdeep: Dragon Heist. I imagine space prevented this, as that book was small while this one is bursting at the seams.

There’s no vertical map. I would have loved a cutaway showing roughly how deep you get and the variable location of each level. Such a map would also have been a good place to put a cheat sheet of the mirror gate network. As it is, you need to make a list of which levels are connected. (But, again, space.)

I’ll be that dick and say it: I am not a fan of the maps. The maps are simplistic monochromatic line art. I find them bland and lacking in details, and can’t be displayed for games, especially on Virtual Tabletops. This design was understandable of Dragon Heist as they were generic and could be used for a couple different encounters. I imagine the number of maps in this book was a factor, as it made more artistic maps cost prohibitive.

I should clarify that this is not a shot at either the skill or artistry of the cartographer; I am sure they worked their ass off on these maps and I’m happy they get to see their name in the credits or a book. That is the best feeling. I would just prefer a different aesthetic to the maps.

The lack of map detail also aggravates another issue: the absence of read aloud/grey boxed text. This means DMs need to parse more information to describe to the players what they see, and can’t even use the map to describe the appearance. While not everyone uses read aloud text, I prefer the option of using it or not. But, as is a phrase repeated often in this review, I imagine space might have been a factor: there simply wasn’t the page count to spare to include adjectives for each room.

The book also has extremely limited art. Each chapter has the half page header and the map. There might be a small added piece, but often nothing else. No art of items or cool chambers or unique monsters or headshots of NPCs. Zero art of Halaster’s “flying saucer” and while there’s art of the mechanical purple worm/ bore machine, there’s none for the “pretty big hate machine”, which gets a very small description with which to paint a description.

Which segues into another complaint. Damn, there is an eff-ton of pop culture “Easter eggs” in the room names. Stuff like “Keep Calm and Carrion” or “Alas, Poor Yarek.” (To get the second example I literally opened to a random page. That’s seriously all you need to do to find a jokey reference.) This is generally pretty ignorable as only the DM need know the room names, but there’s a lot of other goofiness and anachronisms throughout the book. (See the aforementioned flying saucer.) I’m not a player who thinks the game has to be super serious, but my players also don’t need help derailing a session with wackiness and bad jokes. And I don’t enjoy that the book feels the need to hinder people who do want a serious and more dramatic game.

(That said… if you’re the type of gamer who does like goofier adventures, then this might be a big plus.)

The dungeon ecology is so-so. It’s certainly not a implausible early Gygaxian adventure, but it is strained in a few places. Such as having eighty troglodytes in a small region of a layer the size of a city block. It’s not the worst I’ve seen, but it’s weird in places. That said, this is another benefit of the tunnels that “lead to expanded dungeon”, as there could be more than enough space for all kinds of fungi farms or ecologies that simply aren’t detailed in this book.

Lastly, the penultimate level is weird. It’s a fortress/manor of a Waterdhavian noble family that somehow made it a mile underground. It’s just… weird. Not the level you expect to find at the very bottom of a massive dungeon. After fighting past mind flayers, drow, fallen angels, several dragons, and a lich you find… a fallen and corrupted noble family.

The Ugly

What the hell is up with the lava child?! Of all the monsters to directly update in appearance from 1st Edition… (I think I’ll use images from Pathfinder’s Misfit Monsters Redeemed)

A big problem that is only semi-related is the Maps and Miscellany accessory. This folio contains all the maps in this adventure printed on individual sheets and laminated. This would be much more useful if the maps were full colour and detailed: I would have loved a similar product for Tomb of Annihilation. However, given the maps are black-and-white, they’re simple to print off on a home printer. You’re paying for something you can do with $1 worth of plastic page protectors, a free smartphone scanner app, and maybe $3 worth of paper and toner.

Halaster’s plan is nonexistent. Okay, technically he has six plans, chosen randomly at the start (and re-chosen whenever you want). But these are pretty tacked-on and won’t affect your time spent delving. Which I suppose is the point: you dungeon crawl into Undermountain for the sake of crawling through dungeons. But this is very much not an adventure for you if want if want anything beyond the thinnest veneer of a plot. I know not everyone wants a plot, but it’s generally easier to strip one out if you wish to add your own rather than having to invent something.

The Awesome

The adventure features a list of useful fungi. I think this might have also been in Out of the Abyss, but it’s still useful and fun.

There’s a sale price of spellbooks! Useful. And needed for my upcoming game this weekend. Even if I never use anything else in this book, it will have made a positive impact on my table.

There’s a miniature castle that shrinks you when you enter. Fun. But the addition of the faerie dragon make it so much more amusing and hilarious.

Giant golden snail. Nuff said.

Speaking of beasts, there’s a lots of unique and customized monsters. Part of this might have been for space, as they couldn’t make many new monster or reprint unusual beasts from Guide to Monsters, but so often simple changes works. Such as a large grey ooze made from duergar that has extra magical powers. Or crystal golems that are modified stone golems. That’s such a small change and just needs a couple trait tweaks, and yet will work effortlessly at the table while also being evocative. Crystal golems are absolutely going to make an appearance in a future adventure of mine.

There’s lots of small references to other content, most often Dragon Heist but Tome of Foes gets name-dropped a few times as well. These always felt like suggestions of other sources to read for expanded lore, and less like blatant plugs or content required to play. This is a hard balance. However, this does mean connections between this adventure and Dragon Heist are tenuous at best. There’s no direct through line that leads from one to the other. But a remotely skilled DM should be make it work. Especially if the Big Bad is the Xanathar, and you can merge the two by delving to reach Skullport prior to the climax of Dragon Heist.

Final Thoughts

I was initially unimpressed by Dungeon of the Mad Mage. While the dungeon was big, it seemed to lack the inventive traps of the Tomb of Annihilation and the driving story of Acererak’s soul monger plan. Fewer things stood out, in part because of the maps and art. While flipping through the book, there was less to catch my eye and pull me to read a level or section.

Once I moved beyond my initial impression, I grew more favourable to this product. This book isn’t what I want, but I think it’s what a lot of other people want. And that’s an important distinction.

This is very much a big book of almost two-dozen dungeons to make your own. Two dozen old school dungeon modules to throw into your campaign as needed or build a story around. The kind of module Grognaria complained was lost with Dragonlance It’s not the book that has such a cool idea and story that you will drop everything to incorporate into your game, but it is the book you might turn to when you need a troglodyte warren or look towards when work is kicking your ass but you still need to plan a session.

If you don’t want a pressing story and ticking clock, this adventure is much more preferable than many of the past adventures, which were so much more story-heavy. If you want to make your own story or hate having to strip out a story, this volume is perfect for you. Especially if you want to return to a simple style of play where the adventurers wander into the dungeon for the sole purpose of seeking treasure, kicking in doors and attempting to turn denizens of a dungeon against each other. Which really seems to FIT the tone of Undermountain. This product tries to stay true to the spirit of Undermountain, rather than trying to add a deep story while assigning a complex plot to Halaster. It doesn’t try to reinvent it into something that it’s not. And I can respect that.

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