Idea: A cult operates out of a cave near the coast, worshiping a piscine demon lord named Dagon. They are assisted by the god’s fish-like spawn and a demon conjured from his layer of Hell.
Hook: There has been more bountiful than usual fishing in the nearby town, but the fish that have been caught are strange, mutated, and disgusting. In addition, some of the poorer residents of the village have gone missing. Whispers point to a coastal cave being the cause of both the odd fish and the missing villagers, along with rumors of gold.
1. Sitting near the entrance of the cave, smoking a pipe, is an old man with a long, gray beard. Next to him is an empty bottle of beer. (If talked to, he will introduce himself as Jeremiah Finkleton. He says that the cultists don’t attack him because he tells them about what goes on about town, and that in return the cultists give him gold coins to buy booze. He doesn’t know much about whats going on, but he does know he has seem some “strange ‘uns comin’ out from them caves at night, all smellin’ fish like.”)
2. There are crude racks made from driftwood and whalebone, erected near the walls. Fish of unusual shapes and sizes dangle from the racks, evidently drying. (Some of these “fish” don’t even look like vertebrates, with chitinous exoskeletons and compound eyes.)
3. The walls of this room are covered with carvings, showing fish-like humanoids hunting beneath the deep ocean, warring with bizarre beings, and worshiping ancient gods. (There is one part of the carving that seems to depict the fish-people releasing fish into a cove in exchange for human sacrifices.)
4. There is a pedestal made from coral and rock in the center of the room. Small pools of water around the room glow with luminescent algae. On top of the pedestal is a slime covered golden statue, depicting a shark-like being with humanoid features. (The slime on the statue is extracted from a venomous jellyfish, and touching the statue without wiping off the slime causes horrible pain and even death.)
5. People in dark robes chant ominously in a circle around a stone monolith, covered with odd symbols and glyphs. (The cultists will attack when they notice the intruders, and one wields a ritual dagger made from gold.)
6. A still pool of water fills the room, reaching up to one’s knees. Small, snake-like fish which glow with a faint blue light can be seen swimming about in it. (The fish are electric eels of extreme potency, and alarming one can cause the entire pool to be electrocuted.)
7. In the center of the room is a stone structure somewhat like a bird bath, decorated with esoteric symbols. Dark water fills the bowl. (If one looks into the water, they will begin to see the bottom of a vast ocean, with bizarre and eldritch sea-life swimming around, glowing subtly.)
8. Some people in robes sit with crossed legs with their eyes closed. Some of them occasionally take sips from blood filled bowls placed in front of them. (The cultists are easy to sneak past, as they are meditating, but if one detects the party, they will inform the others and attack.)
9. Hanging from hooks in the walls are several waterlogged human bodies, evidently a few days old. They show evidence of bite and claw marks. (Upon closer inspection, every body has been drained of blood, their throats slit with a knife of some kind.)
10. Disgusting, fish-like humanoids chant and gurgle around a circle of luminescent algae. Contained within the circle is a large tentacled beast, resembling a cross between a crab, a squid, and a piranha. (One of the fish people wears several circlets and a crown, all made from gold of the highest quality. In its hand it wields a magical staff made from a bone. This staff allows the wielder to cause the lungs of any victim within line of sight to fill with water, drowning them on dry land.)