Last night, our Wednesday game group started The Lost Caverns of Tsojcanth (Advanced Dungeons & Dragons module S4). This is a continuation of our PC party that previously explored the Forgotten Temple of Tharizdun (WG4). Both adventures were written by Gary Gygax, and are well-loved classics today.

Where Tharizdun was a pitched battle, followed by a descent into a sinister temple dedicated to forgotten alien deity, Tsojcanth is the exploration of a dungeon that was the last holdout of a dangerously ambitious archmage who trafficked in bound demons.

But first the Lost Caverns of Tsojcanth must be found, requiring wilderness exploration.

Nearly a century ago the Arch-mage Iggwilv sent her evil minions to conquer the lands around her abode. So successful was she that the Marches of Perrenland were subjugated for a decade, and great indeed was the loot brought to Iggwilv’s lair in answer to her insatiable demands for treasure. Legend states that the arch-mage gained much of her prowess from discovering the Lost Caverns of Tsojcanth, wherein was hidden magic of unsurpassed might. It is certain that Iggwilv ruled her domain from these caverns. There she also conducted arcane experiments and rituals, trying to further increase her powers.

These experiments were her downfall, for during one she accidentally freed the demon Graz’zt, whom she had imprisoned and forced into servitude. There was a terrible battle, and although the demon was forced to flee to the Abyss, Iggwilv was so stricken from the contest that her powers and strength were forever lost. With the wane of her evil, Iggwilv’s realm was sundered. Her former henchmen and slaves stole her treasure and scattered to the four winds in the face of enemy armies. The arch-mage, however, used the last of her power to prepare a hiding place in the caverns for her remaining wealth. Legends say that this included several tomes of great power and the fabled lamp called Daoud’s Wondrous Lanthorn. What else might be hidden no one knows, for no one has yet discovered Iggwilv’s hoard.

That Iggwilv is long dead and gone cannot be doubted. Until recently, though, the stories of her secret cache of treasure in the Lost Caverns of Tsojcanth were regarded as another grandfathers’ tale to amuse the younglings. Cartloads of tapestries and rugs, statues and rare art objects have been recovered over the years as well as chests of precious metals, sacks of coin, and coffers filled with gems and jewelry. It was believed that all her treasure had been looted, and that no magic or wealth remained. However, recent investigations have indicated that the magical lanthorn did exist and that Iggwilv possessed it. Iggwilv’s lair was definitely located somewhere between the gorge of the Velverdyva River and the hills east of the town of Krestible. The realms of luz, Perrenland, and Ket have sent expeditions into the Yatil Mountains seeking the exact location of the caverns; the few that have survived have all failed.

from the module Introduction

The Lost Caverns of Tsojcanth (S4)

1982 … Two 32-page booklets + 3-panel cover … Gary Gygax … TSR 9061 … ISBN 0935696725

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One of my all time favorite dungeon crawls. Not only do you get a clever adventure written by Gygax himself, but the second booklet is entirely devoted to new monsters and magical items.
Many of the creatures are now AD&D canon: Bodaks, derros, marlgoyles, xag-ya/xeg-yi, and more. Also various demons, minor, major, and demon princes like Graz’zt.
Magical items include Slippers of Spider Climbing, Lens of Detection, and the Horn of Fog. There are also two arifacts for you to drool over.
Six new spells involve the summoning and control of extra-planar creatures.

The connection to Tharizdun

Tharizdun and Tsojcanth are paired modules, both set in the old school Greyhawk campaign setting, found in the rugged Yatil Mountains between Perrenland and Ket. Tsojcanth has a large wilderness map that the players must navigate. The Tharizdun area map is a much smaller area, curiously enough – both maps are shown to scale in the right image.

Did you know Tsojcanth was the 2nd module ever written for D&D?


All player characters are level 8. 

I’m running this classic AD&D adventure by Gary Gygax using Dungeons & Dragons 5th edition (5e) on Roll20 VTT online tabletop, converting on the fly from the original module. You’ll be seeing screen snips from the session.

I’m attempting to hew close to the spirit of the original module. Where Gygax states a direct effect, I’m going with that over whatever the 5e rules would say for that situation.

See how Tharizdun ended for this party (links to prior sessions as well):

Gearing Up

The party had accumulated quite a bit of loot from Tharizdun, and were miles from civilization, so I allowed them to fence their loot to the gnomes of Gnome Vale (minus a 20% markdown of course).

Here’s a list of special items they could (and did!) purchase:

All items are unique except potions, which have a limit of 5.

Weapons / Armor

  • Dagger of Venom +1 (3,000 gp)  Expend a normal action to cause poison to coat blade 1/day. DC15 Con saving throw or take 2d10 poison damage and become Poisoned for 1 minute.
  • Shield +1 (2,000 gp) man-sized
  • Chainmail +1 (3,000 gp)  man-sized
  • Dwarven Plate +2 (6,000 gp)  if an effect moves you against your will along the ground, you can use your reaction to reduce the distance you are moved by up to 10 feet.
  • Arrow of Elemental Slaying (1,000 gp)  Creature must make a DC 17 Constitution saving throw, taking an extra 6d10 piercing damage on a failed save, or half as much extra damage on a successful one.
  • Arrow of Giant Slaying (1,000 gp)  Creature must make a DC 17 Constitution saving throw, taking an extra 6d10 piercing damage on a failed save, or half as much extra damage on a successful one.


  • Bag of Tricks, Tan  (3,000 gp)   Pull random animal ally from bag 3x/day
  • Amulet of Health(5,000 gp)  Con is 19 while wearing
  • Deck of Illusions (2,000 gp)  Draw and throw down card that becomes illusionary creature that you control.
  • Dimensional Shackles (5,000 gp)  Restrain limbs of an incapacitated opponent and prevent dimensional travel.
  • Ring of Evasion (5,000 gp)  This ring has 3 charges, and it regains 1d3 expended charges daily at dawn. When you fail a Dexterity saving throw while wearing it, you can use your reaction to expend 1 of its charges to succeed on that saving throw instead.
  • Ring of Feather Falling (5,000gp)  When you fall while wearing this ring, you descend 60 feet per round and take no damage from falling.


  • Healing Greater (200 gp)
  • Healing Superior (500 gp)
  • Diminution (700 gp)
  • Animal Friendship (400 gp)
  • Climbing (300 gp)
  • Growth (500 gp)
  • Resistance Necrotic (400 gp)
  • Water Breathing (400 gp)

The Expedition Launches

Only 2 days into their hike, the party ran into a pack of gnolls!

The wilderness encounters are randomly generated from a table in S4. Since I don’t know what the party will be encountering ahead of time, I have some mountain maps set up in Roll20 to quickly populate. Here, I am using one of Dyson’s maps, looks like a quick sketch from a game he was running.

Both groups spotted each other. The gnolls charged in a loping run!

The group was a bit surprised at the range involved (400 feet initially), being more accustomed to dungeons. It took some time for the groups to close the distance, and the melee characters could only wait.

Soon the party got off a few long-range shots. A gnoll or two were able to score some hits on the party with their longbows.

Then the spellcasters engaged, burning the gnolls with Fireballs and Wall of Fire spells.

One gnoll, seeing many of his pack-brothers burned to death in two fireballs, retreated, but was slain by the gnoll pack lord!

Now the gnolls were closing into melee range.

Continued in the next session:

See Also: