So off the California coast wreathed in perpetual storms, fog, & weather phenomenon I've got X1: "The Isle of Dread" (1981), by David "Zeb" Cook and Tom Moldvay. The Isle is part of a chain of islands that connect to Venger Satanis's Islands of Purple Haunted Putrescence. These island chains exist in on both Earth & Hyperborea simultaneously. Ships have been getting lost or destroyed for centuries. There's also a deadly connection with some of the elite cults that have been operating in the Hollywood hills. The Baleful Sorcerers of Tsathag'kha have been initiating & sacrificing the elite in rituals dedicated to the Clark Ashton Smith Great Old One Tsathoggua.
So I've had this Godbound/Cha'alt campaign going for quite awhile. The cults of Tsathoggua have been making massive in roads into the hills of Hollywood. I dusted off Venger's Slaves of Tsathoggua adventure & there have been hints of something very powerful & supernaturally dangerous in a cave on one of the purple islands. Here the The Baleful Sorcerers of Tsathag'kha have reign over an ancient village where a treasure is rumored to be guarded by incredibly deadly monsters. Only those blessed by Tsathoggua & part of the inner mysteries of the Old One may enter the caverns. So why use The Islands of Purple Haunted Putrescence? Its not only a great hex crawl, but it’s also a great little campaign source book. Part of the background that was hinted in last week's game is about the primeval war between Earth's Atlanteans & the monstrous, mind-bending creatures known as kopru.
The Kopru are living weapons left over from the Deep Ones who were actually behind the extinction of the Atlanteans. This brings me to the fact that the church of Dagon is using the Isle of Dread to make a big push to return to Earth & awaken their brethren beneath the seas of Earth.
Jeffrey Talanian's Mystery At Port Greeley adventure has this happening on Hyperborea. The adventure hints at the church of Dagon about to engulf AS&SH! I've decided to make the fantastic adventure a part of my campaign by having my AS&SH find out about the link between the church & their plans for Earth!
There are deep links between the cults of Tsathoggua & the church of Dagon! Both see Earth as a prime opportunity & resource to be harvested. Those within the Black Pyramid of Cha'alt wait & watch with fetid eyes!
Two killer free resources that that I've used with this campaign for this leg are Threshold magazine issue #3 Sea of Dread & Issue #4 Sea of Dread.
Between the maps, the information, the background, etc. within these two issues there's a ton of material to really help flesh out even more of the Isle of Dread & the seas that surround it. These can be incredibly useful for OSR games!