[Review] Caverns of Thracia (OD&D); Transition

[Adventure]
Caverns of Thracia (1979)

Paul Jaquays (Judges Guild)
Lvl 1+


Caverns of Thracia is of legendary status and considered by many to be the greatest adventure of all time. I have been putting it off. I am not ready, I thought. I need to run and read more adventures. Today I am finally ready. Today we are going to see if it lives up to its reputation.

CoT is a landmark publication, a liminal space between the wild days of OD&D and the more mature, thematically focused days of AD&D 1e. Within its 79 pages are contained all manner of tricks and traps from that primordial epoch, harnessed with a laser focus and a thematic fealty that makes them all the more effective. In the past there is the wildness and abandon of Night of the Walking Wet and the sublime pulp fantasy adventure of Dark Tower. It is almost a megadungeon, 4 levels, 2 sub-levels, with factions, plentiful secret areas, multiple methods of egress, and all manner of deadly terrors.

Lest we mistake the mid-witted teachings of the latter day OSR for truth, it is not conceptual density or novelty that is the source of its enduring power, but rather the opposite. There is something unmistakably archetypal about Caverns of Thracia that transcends any single source of inspiration but rather taps into the substratum of heroic adventure that fuels countless volumes of adventure fiction. We explore tomb-corridors guarded with spear traps, brave swinging rope-ladders spun across chasms, inch forward past a narrow ledge with a roaring underwater river below us, and confront deadly pseudo-naturalistic horrors like a Giant Spider or the tentacles of a giant octopus monster. This is all integrated seamlessly into the framework of OD&D by a master craftsman, there is no hint of tourism, or misaligned priorities. All of it is spiced with a veneer of history and versimilitude, of ancient tongues, fallen kingdoms, extinct civilization and the horrors of distant antiquity.

On some remote hilltop or island, the ruins of the ancient kingdom of Thracia await exploration by those seeking gold and glory. Once the site of a pseudo-minoan kingdom, overthrown by its beastman slaves, now the caverns below its ruins are inhabited by their descendants, the degenerate worshippers of the death god Thanatos, and below and among the caverns and catacombs of Thracia, an even older power is stirring and gently biding its time. A list of short but punchy rumors follows ‘The Hall of Laughing Skulls leads to riches untold!’, and we are soon off into an adventure that spans centuries and will have the characters face off against all manner of deadly and ancient perils.

Craftsmanship permeates the entire work without it feeling bloated. Random encounters are extensive and varied to the point that the module recommends rolling in advance. This is no idle warning. Gnoll patrols armed with all manner of specialized weaponry and accompanied by a fearsome retinue of lizardmen henchmen, tribesman slaves, dogbrothers or minotaurs. The feral descendants of the ancient Thracians, worshippers of Thanatos. The random encounters alone can get pretty vicious and Thracia does not hesitate to confront the players with threats that are better avoided then fought, less dire casualties be taken.



As is always the case with the best module writers, the map is a delight, so far beyond merely a framework for disconnected encounters. Nodes and crossroads are wound around eachother, bissected and enveloped by secret passageways, connected by stairways and bottomless chasms. Hints in lower areas lead back to secret areas in earlier levels, while shafts or teleporters allow one to explore the area in a variety of ways. Let me give you an example of the subtlety of Jaquays in action.



So room 9, itself a secret room, leads to room 13 and then to a crevasse. However, both the entryway to 13 and the one leading to 11 are concealed by illusion, so you can’t see them from 15. The way you could discern the existence of crevasse hallway 11 is to first find secret door 9a (there is a hint leading to it later on), find room 13, look out over the crevasse, think nothing of it, then either traverse the rope ladder at 15 or do that before and suddenly realize the opening to 13 is concealed behind an illusion, THEN you have to consider maybe there is another illusionary opening too, and THEN you find room 11. It is a type of design where you will go back to ‘explored areas’ and find new secrets long past your second or third runthrough.

The maps are the opposite of linear. There are so many different ways and interconnected passages, often secret, or difficult or dangerous to traverse, that connect everything together that if a particular direction is unrewarding another method of egress can always be attempted. There are hidden sublevels that might not be found until the very end of the adventure, or even at all.


The first two maps make exquisite use of natural and pseudo-natural hazards to supplement the usual pit and spear traps of a tomb. Rope ladders, crumbling ledges, underwater-ridges, chasms. S&S adventure and the mythological substratum from which it taps are not just about people fighting giant animals but about man versus nature. Perilous heights, giant bats pitching you off rope ladders, a rapid current with a great spider-web spun across it, an edge crumbling if you stand on it, it is so classic it is archetypal, the stuff you imagine happening in adventures before you can even read. Far from aping the form of the Appendix N, Caverns channels its spirit, which exists beyond and above any single element or resource.


Tomb adventures fall into the trap of consisting only of protections, traps and the dead. They can seem lifeless. CoT largely avoids this pitfall by populating its spiralling minoan tomb complex with death-worshipping barbarians, checkpoints of vicious gnolls, tribes of man-eating lizardmen and all of them existing under the yoke of the savage Minotaur King. These creatures use barricades, spyholes, reinforcements, different weapons and all manner of intelligent procedures to resist the character’s egress into this subterrenean world, and some among them have the power of wizards. Occasionally, the GM will have to do a little heavy lifting, as, say, the Palace on level 4 is quite densely populated and only careful note-taking beforehand would allow the aspiring GM to run the battle as it is surely intended; a massive chaotic shitshow of an encounter. If the PCs give the inhabitants time, they will use the sorcerous objects in the palace to enact a dreadful revenge against them.

The adventure also channels the mythic elements that make up its components exemplarily well. There is a menace to the deathless inhabitants of the tomb that extends even to the tried and true entries in the Monster Manual. It’s not ‘mummy’ it’s ‘mummified king of ancient Thracia, bearing soul-stealing black sword.’ Those who enter the sanctum of the Dark One, if they are at 3 hp or below, will see a shadowy figure in a dark robe watching them, extending its hands as if to embrace them. What do you do? Or what of the treasure chests guarded by spectral jaws that, if not defeated, will return turns later, stronger and more formidable, until they are the party has been expiated? Do I go, yes I must, into level 3A, the final resting place of king Agamemnos, empty but for a handful of the restless dead, and a bronze statue of Thanatos which prowls the halls, firing paralyzing rays. The enchanted statues in Caverns of Thracia are as deadly as they are inexorable. You can open any random page and find an encounter endowed with this mystical property. A deadly stone statue following the players, if it is destroyed it will merely regenerate unless the PCs find some way to deal with it permanently. Or say, the mystic black armor you encounter who challenges the party to a single combat to the death. Archetypal forces are herein unleashed.



The archetypal and the ineffable are herein united. What do we say of a room coated in frost, with a door that exudes a hideous freezing death fog and stones that sap the very life from the characters? What more do we say when we can rescue one of its near-frozen occupants, and if she is healed, have a companion that speaks only the ancient Tracian tongue, and for whom the palace revolt wherein King Agamemnos was slain by his beastmen servants is not distant legend but living memory. NPC companions, prisoners and the ability to ally even with factions is a common thread throughout the adventure, but it is but part of a greater whole, adding to it but never overwhelming all the other notes.

There are more subtle elements that can be difficult to pin down. The weird and ineffable, the unknown. Strange magical effects, teleporters, methods of destroying them, halls of stone hands, or a room that can entomb the characters inside forever. A great sphinx in a hall lit by witchfire, operating as a sage. From a pentagram, a glowing skull face answers one question truthfully and brands those so asking the question with the mark of Thanatos. Caverns uses classic monsters but you never get the idea that it is predictable or trite. The supernatural is not limited to the entries of a bestiary, or even the words of each entry. The Minotaur King is no mere set of stats but a supra-human menace that the stats can only dimly hint at. Take something like the strange cabin by the river, with a dead halfling, and a cursed amulet that will keep attracting fanatical lizardmen until it is slain. There is method to the madness, but the supernatural element is never predictable.



When you have delved through about 3.5 levels of Dungeon and you are about getting into a routine the adventure throws a wicked curveball and suddenly you can teleport or take a cage on a winch down into a cavern under the complex, lit by a strange inner sun, and populated by verdant trees. This is the one area that I think could have used more elaboration (according to Melan, the Necromancer games version has expanded this area considerably). Suddenly you are in a forest, inhabited by Dryads plagued by the cruel Reign of the Minotaur King, searching for allies and a means to break through a great enchanted hedge. The palace proper is likely to be the site of a humongous pitched battle, with classic monsters from greek mythology, Harpies, Minotaurs and a fucking Hydra, being trotted out in short order. There are magic bowls that can be harnessed to possibly transport the characters (and if they are unlucky, the reinforcements sent to kill them) all over the dungeon as, in a flourish known to Doom 2 map designers everywhere, the level suddenly opens up as enough progress has been made.

The palace proper is going to be anything from the site of a savage battle to a place for infiltration, recoinassance and perhaps even negotiation. I think the only point is that the Dungeon level below the palace feels a bit weak after all these marvels. After gnoll harems, a Minotaur King, X hideous enchanted killer statues with unique powers and 60 something Gnolls and lizardmen, yet more corridors and hallways don’t really get the blood pumping in quite the same way. The escape pods are a nice touch, and I won’t say no to a major treasure vault, but it does feel a bit weak. Fortunately, it is not quite the true ending.


There is a hidden tomb, in the centre of the dungeon, of the Lizard King. It is mostly desolate, but the few encounters are terrible in power, and the treasure is great. In retrospect the use of Lizard Liches in Artpunk works like Maze of the Blue Medusa or Skerples’s Tomb of the Serpent Kings might be attributed to Jaquays, for while these authors were not exactly renowned for being studious, the works of Jaquays had garned particular attention in the artpunk circles. Regardless, a final confrontation and the risk of perhaps setting loose an immortal Reptile King with Lich powers into the world is a fine capstone to what is going to be one hell of a memorable campaign.

I have mentioned the encounters before in passing, but CoT should be required reading for everyone who is still hopelessly confused about Challenge Ratings or Combat or Combat as a Failure State or whatever other nonsense. The idea is that combat occurs and is inseparably bound to fantastical adventures. However, combat does not mean, fair combat. In order to create a game where the PCs are on their toes and will resort to a plethora of strategies besides rolling d20s and hoping they roll high enough Caverns occasionally throws brutal encounters at the players that they will either have to avoid or at least require some sort of gambit, scheme, grand strategem or edge in order to overcome. So while it is mostly very fair in the type of obstacles the PCs encounter, on rare occasions it is spectacularly unfair in order to keep a palpable sense of menace and keep the PCs on their toes. There is also much use of situations where players can get knowledge from the monsters to help them bypass difficult encounters or find extra treasure, such as the guardian Manticores on level 4 that will not attack if the correct password is spoken aloud. These sorts of situations encourage a type of gameplay that is rather higher then mere slaughter, although certainly there is plenty of that to be found also.

Treasure is great. Maybe a little stingy at first but more then enough. At this level of mastery it should be assumed treasure is not going to be x1000 gp worth of gemstones and then wham bam thank you mam. You can assume it is properly guarded, concealed, trapped, ornate, embedded into the setting and that each amphorae of copper pieces adds to the feel of exploring a mythic underworld and returning from it laden with reward as a sort of recursive Hero’s journey with a lot of false positives and dead Moonglums.

As is often the case with these sorts of seminal works it is impossible to point to any one element and attribute the work’s success to it. Rather it is a higher level synergy between all of its components that elevates it. There is no ‘trick’ to Caverns of Thracia in the same way there is no trick to Halls of the Fire Giant King. It provides enough innovation and novelty to feel fresh while keeping both its feet firmly planted in the shared corpus of Fantasy Adventure Gaming. It resonates because it is archetypal, relatable to anyone from Appendix N converts to a 12 year old that has read the myth of theseus and has seen Indiana Jones. If one wants to enjoy it on some sort of cerebral level as fantastic exploration of a fantastic milieu the means are certainly provided but even complete illiterates that just want to gain xp and kill gnolls are going to have an absolute blast of a time and do so in style.

One can argue it is perhaps a bit dense (as Jaquays himself mocks the idea of 1/3 empty rooms) but I suspect this will be no major obstacle, as there are indeed plentiful rooms that are quiet and not laden with armfuls of gold. Your player’s don’t need to learn how to play DnD differently in order to brave Caverns of Thracia, rather, it is an exultant, platonic celebration of normal DnD, and the more power to it. It would probably require quite a bit of note-taking to run smoothly, particularly the many entrances between different levels bear close watching, as do the few times when pitched battles involving multiple combatants in nearby rooms will take place. The upper ruins are a bit desolate, with two minor buildings only, and for once, this fantastic megadungeon does not have a suitably impressive introduction set piece, which is surprising considering the author’s previous work. There is also less of the Jaqueysian trademark smut, although the Gnoll hareem and the interruption of a Dog Brother mid coitus with three young gnoll ladies is a bit risque.

I must cite Gabor Lux for pointing out that he considers Dark Tower to be the superior entry and I do think its more ambitious scope, harder edge and brilliant mapping gives it the edge, to say nothing of the weaker 4th level of CoT but this is like arguing whether the Illiad is superior to Paradise Lost. Both entries exist in stratospheric heights that are approachable by few and matched only by Gygax in his prime. Worth playing and replaying, and can be picked over endlessly without ever fully being known. There are too many superfluous low level adventures in the OSR, but this will never be one of them.

*****











28 thoughts on “[Review] Caverns of Thracia (OD&D); Transition

  1. I am looking for resources that list connections between levels, NPCs and rooms/ items that respond to other rooms

    Help DMs where can I find this?

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  2. I finished reading Caverns of Thracia a week or two ago. While I consider Dark Tower to be the superior adventure from the two, it feels much more intimidating and harder to run.

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  3. I picked this and the Ready Ref Sheets book up blind at a second-hand store around 1987, not long after acquiring the Best of Dragon vol I reprint and realizing for the first time that there was not only a version of the game before the Basic sets and AD&D but that it had a different feel from the later stuff and a while scrappy DIY fan-culture around it. It would be another year or so before I would actually see an OD&D set, but I was already totally enthralled and spent the next 20 years or so chasing and evangelizing that version of the game over the Dragonlance Forgotten Realms shlock it devolved into, until the OSR stole my shtick and went so hard into OD&D and megadungeons that my contrarian streak kicked in and drove me back to Gygax-style AD&D.

    As I mentioned when you reviewed this, I think Dark Tower is a little better than this because its bad guys are more dynamic and it’s more action-oriented – when I tried to run this BITD the players got confused and bored – but it’s still unquestionably a masterpiece and one of the half dozen or so best things ever published for the game.

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  4. Great review, this is one of the greatest. I give the lesser known Dark Tower a slightly higher score, probably purely because of the level range.

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  5. I ran both Thracia and Dark Tower in the early 80s and loved them both. They, along with Tegel Manor and Thieves of Fortress Badabaskor were by far my favorite adventures to run back then. I agree that Arden Vul draws heavily in inspiration from Thracia, in a good way.
    I think my one quibble with Thracia is that , in my opinion it lacks sufficient treasure and what is encountered is not epic enough to match the scope of the adventure. By contrast, Dark Tower is just full of epic magic items.

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    1. Jaquays mentions treasure is purposefully rare but I think the sums sort of add up, within the XP curve. It doesn’t seem under-powered but by comparison Dark Tower definetely has it beat.

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    1. I used the original name for archival purposes and ease of reference. I think I mention the namechange to Jennel in my review of Dark Tower? I haven’t been keeping up with american cultural mores in years and I don’t think I am coming back.

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      1. You’re much better off, Prince. It’s a real shit show of “everything offends somebody” here.

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  6. You pass the test of reviewing excellence. Caverns of Thracia is a beautifully crafted classical adventure. Repeating myself from another thread, I don’t think “layers of history” has ever been done better. For me, it is also the perfect size for exploration: it is immediately apparent that a five room linear dungeon has little scope for this facet of the game, but there is a danger with the seemingly never-ending megadungeon that you don’t make connections, and miss interesting features when you don’t retrace your steps.

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  7. Well now I’m beginning to wonder if the Lizard King isn’t meant to be a reference to Jim Morrison and the Doors. I’ll have to read through this again when I get the chance.

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    1. Okay nevermind, that wasn’t it. I’m glad you reviewed this. Bryce got me interested enough to buy it a few years ago but I never got into it. It is a fascinating module. I may have to try to add it somehow to my campaign.

      The other interesting thing of note when reading this module is how Jacquays spells pedestal (pedestle?). It’s slightly jarring.

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  8. The genius of Jaquays shall also be contextualized with the mode of production: Judges Guild did just push the authors for more and quicker content output. There is a legion of rickety and even dubious modules, converted-notes and half-baked ideas from JG. And they were fine with it. JG did also not applaud Jaquays producing quality, “write faster!” they apparently said. That any good came out of that process heightens the contributors dedication to the game.

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