Sulphur pits of Nathazda is an adventure for the Spelldancer RPG but could be easily modified to work with any percentile based system.  This is not one for inexperienced characters, but with the Spelldancer system you can create experience characters right from the start.  The adventure includes  some sample characters you could either use as NPCs or PCs.

Like other Gethsemane Games adventures part of the dangers the party will face are from the environment itself not just from the creatures within.  In this case the creatures are demons and ewwww, some of them are gross!  Demon maggots anyone? The adventure also answers the question of what happened to one of the missing Demon Lords of the Malmori, and in our game we actually found ourselves making an alliance with it to defeat the demon we had come to kill!  As usual there are some interesting ideas for expanding the adventure.

At first glance it looks like a fairly short dungeon crawl, and it is ( about 2 nights play perhaps?) but then in Spelldancer you don’t want to be in a dungeon too long as a few good hits will put you in a bad way, and believe me, in this adventure characters are going to get hit sooner or later!

I loved the feel of this adventure and it was just long enough for us, any longer and we wouldn’t have been able to complete it without coming out, healing up and then going back in.  your players should be prepared for the very real possibility of having a character or two killed in this adventure, especially in the final showdown.