CAUTION: This series of articles contains many spoilers concerning the modules D1-3 and should only be read by DMs and those players who will not be actually playing through the series at any time in the future. Failure to observe this caution will lead to a marked lack of enjoyment in the adventures.
Published back in what some old-time gamers fondly remember as the heyday of the original Advanced Dungeons and Dragons game, 1978, the series of adventure modules D1-3, collectively known as the “Descent into the Depths of the Earth” series from the title of the first module, are some of the best-known and yet least-understood elements of the Dungeons and Dragons campaign setting known as the World of Greyhawk. They are, in order, “Descent into the Depths of the Earth”, “Shrine of the Kuo-Toa”, and “Vault of the Drow”. All three were used as the official tournament modules at GenCon XI.
When correctly played and DM'ed, the “Descent” modules are actually a model for those who value political intrigue, role-playing, and exploration of what was (at the time) a new environment for play. They are also, naturally, quite deadly, and foolish or unprepared characters will find themselves at -10 HP in short order. Neither hack-and-slash nor stealth-and-stab should prove worthwhile strategies for these modules.
It should be noted that these three modules were later republished as part of the supermodule “Queen of the Spiders”. Except where noted, this article makes reference to the original monochrome-cover modules published in 1978. I deliberately eschew the term “Underdark” for the areas described in D1-3, as that term was originally coined by author Ed Greenwood for his own “Forgotten Realms” campaign, and to apply it to the World of Greyhawk has always struck me as gauche.
D1: Descent into the Depths of the Earth
This module begins at the entrance to the Depths, across the river of lava found at the end of “Hall of the Fire Giant King”. The players have found a partial map of the underground area, and know that the drow are to be found within. Other than that, they are lacking in any sort of background, this being the first encounter with the drow other than their appearance in the “Hall of the Fire Giant King”.
This very lack of information, however, should be seen as an opportunity for the PCs to collect their own intelligence on what is going on under the sunlit mountains of Oerth. And an astute DM can give subtle clues as to some of the rivalries and divisions within the underground communities. The Descent modules, more than most, reward a DM who has thoroughly read through them, picking up not only the locations of monsters and treasure, but also the subtle points regarding the political situation. To this day, many Greyhawk aficionados don’t realize that Eclavdra, the chief villainess in G3, was not a servant of the demonness Lolth, but actually the chief rival of the Lolth-worshippers! It's worth noting that two different factions of drow can be found in Snurre's hall; the DM has an opportunity to lay the groundwork of the “factionalized enemy” theme before the PC's enter the Depths.
Some points worth emphasizing:
If the PCs manage to do damage to the Mind Flayers in the area, and can provide proof to the drow of this, they are 90% likely to be rewarded with a pass that will get them through any drow controlled area without harassment (D1, p. 3). This of course implies that the drow are going to be open to parley when encountered. The DM should not forget this; many if not most of the drow the PCs encounter are not going to be instantly hostile unless they have been alerted to the presence of the hostile PCs. Unless they're on alert, and looking for the PC's, the drow aren't going to “shoot first and ask questions later”! This doesn't mean they'll be fools or pushovers, just that they won't instantly attack.
How can the PCs figure out that the drow and Mind Flayers are at odds with one another? In the second encounter area of the module, in hex M-12, the Mind Flayers are questioning a captive drow merchant. Even if they don’t manage to get him out alive (and it would be exceedingly difficult, in all honesty), the mere fact that the Mind Flayers had captured a drow should get the PC’s minds working. An interesting twist would be if the PCs decided to try to get the Mind Flayers as allies against the drow! There's got to be an illithid city out there.
One of the most interesting things about the “Caverns and Warrens of the Troglodytes” (the main encounter area, at hex Q-19) is that it is entirely possible for the PCs to glide through it with minimal fuss. Those PCs who managed to gain the trust of the drow will simply pass through the cavern, and actually be aided by the garrison in area 6. Those who are not allied with the drow, but who are following the players map and thus looking specifically for a northwesterly exit from the caverns will at most have to deal with the garrison and its 18 soldiers, and at most only those monsters encountered in the western side of the caverns (areas 1-9 on the map). This is definitely an encounter area which does not reward the “wipe out everything” mentality; in a test of endurance such as the Descent series, taking time to spread out bits and pieces of bugbears, troglodytes, and trolls around the floor of the cavern is not worth the relatively minor treasures to be gained thereby. As DM, you should be ruthless in punishing such a lack of focus, and don't be afraid to drain the PC's of their healing magic and other supplies. That is one of the functions of the main encounter area; distraction.
The key to an enjoyable running of the entire series is that the PC's must not thunder their way through the place. The Depths are not a standard dungeon setting; they are a living, breathing wilderness and should be treated as such by the DM. By seeing signs of “normal” habitation; merchant caravans, kuo-toa pilgrims, etc. the PC's should get enough hints to attempt a strategy of bluff, rather than bash, to make their way through.