" The PC's are based at a keep & investigate a nearby series of caves that are filled with a variety of Chaos monsters.The Cult of Chaos has been on the move! ""The Keep on the Borderlands is a Dungeons & Dragons module by Gary Gygax, first printed in December 1979. In it, player characters are based at a keep and investigate a nearby series of caves that are filled with a variety of monsters. It was designed to be used with the Dungeons & Dragons Basic Set, and was included in the 1979–1982 editions of the Basic Set. It was designed for people new to Dungeons & Dragons."
This is the classic D&D module! The wide open full "sandbox" nature of the setting makes it suitable to drop into almost any campaign and especially Astonishing Swordsmen & Sorcerer of Hyperborea second edition. The keep is a perfect venue for PC's for characters to base themselves in before setting out to explore the Caves of Chaos!
So how does this relate to Clark Ashton Smith? Well, it all comes down to the Temple of Elemental Evil by Gary Gygax & Frank Mentzer which in the past has seen the Caves of Chaos as an outpost of the temple itself. The place is a shrine to the cult of the elemental evil. But surely there's no Clark Ashton Smith connection to the Caves of Chaos? Well as a matter of fact there is. As a part of the Hyperborea cycle by Clark Ashton Smith 'the Coming of the White Worm' highlights the cult of Rlim Shaikorth which bares a striking resemblance to many of the aspects from the elemental evil cult.
The fort from 'Keep of the Borderlands; is the sort of back water fortress that along with 'The Village of Hommlet' seems exactly like a key part of a national defense network before the coming of the 'Green Death'. These forts might have served as a fulcrum fortresses with the village keeping these forts supplied with food,manpower,& provisions. The village of Hommlet itself a part of a trade route that stretched across Hyperborea. The caves of Chaos were part of a super science manufacturing plant that turned out bucket loads of humanoids made from the material of Abhoth
" (H]e described a sort of pool with a margin of mud that was marled with obscene offal; and in the pool a grayish, horrid mass that nearly choked it from rim to rim... Here, it seemed, was the ultimate source of all miscreation and abomination. For the gray mass quobbed and quivered, and swelled perpetually; and from it, in manifold fission, were spawned the anatomies that crept away on every side through the grotto. There were things like bodiless legs or arms that flailed in the slime, or heads that rolled, or floundering bellies with fishes' fins; and all manner of things malformed and monstrous, that grew in size as they departed from the neighborhood of Abhoth. And those that swam not swiftly ashore when they fell into the pool from Abhoth, were devoured by mouths that gaped in the parent bulk.
—Clark Ashton Smith, The Seven Geases"
Forget little villages of humanoids, these forces are fully formed and birthed out into the world ready to take down Hyperborea at a moment's notice. The cult of the elemental evil religion is insidious because of the way that it spreads its power from village to village through the lowest ranks. The spreading of it has enabled the consolidation of power. This rise of power centers around the humanoids of B2. I think that there might be demonic influence from behind the scenes.
B1 can be the jump off point to really excel a campaign into legendary status where heroes are being hunted by the forces of darkness leading back into the adventure arch of the Temple of Elemental Evil. The forces are beginning to swell again as rank after rank is filled by vast numbers of humanoids. The caves of Chaos is the key to really bringing home the fact that the whole area is rife with agents and fifth columnists.
All in all this set up and adventure arch is perfectly timed to bring even the strongest players to their knees. Betrayal, background maneuvering, double dealing, assassinations, etc. are all a part of B2 Keep on the Borderlands. The adventure that you cut your teeth on is now a puzzle piece in an ever expanding Sword & Sorcery campaign waiting to happen!