Blood for the maw. Lives for the Core of Darkness. Let our enemies feed the endless hunger of the great one. Lest it sets its harrowing fury upon us…
Lore of the Deep Ones
The pantheon of deities known to humanoid societies provides ample choice for varied cultures. Many believe that those deities are the only ones in existence. For many, it is so. However, strange, elusive cultures are privy to forgotten knowledge, like the culture of the deep ones. They are cultish, amphibious fish-people. They lurk in deep water and sunless caverns. The deep ones worship gods whose names have not been uttered by human tongues.
Tentacled Nightmare
Centuries ago, seeking guidance and madness, a deep one priest found a deity’s avatar deep within a flooded cave system. The deep ones built a shrine by the tentacled abomination, to worship it and to commune with the inebriating madness it sires in the fish folk.
The being’s name can be roughly translated as the ‘Core of Madness’. The deep ones often bring captured enemies, mostly merfolks, and sacrifice them in foul rituals before the tentacled nightmare. The flooded caverns were cut off from the sea by earthquakes decades ago and can only be accessed by the deep ones with teleportation spells. They come less often because of that.
Unexpected Find
Two weeks ago, human mining prospectors stumbled upon a collapsed chamber and stairs while seeking mining veins. The prospectors pulled a wall tile, fled back to town, and brought it to a renowned archaeologist for study. The mining operation is eager to continue its exploration efforts but they heed the scholar’s warning. He wants to explore the underground compound first.
Adventure Hook
- Escorting Job. Barilous, a renowned archaeologist, hires the characters to escort him into a recently discovered ruin in a nearby coal mining site. He has a wall tile recovered by a prospector that bears a fish-like sigil. He suspects the presence of fish-folk (100 gp, 4 XP).
Level 5 Adventure
- Danger. Risky. Check for a Random Event every 2 crawling rounds and after loud noises (3-in-6 chance).
- Light. Some areas have magical light sources; the rest are in darkness. The denizens are dark-adapted.
- gibbering. A barely-audible, unintelligible gibbering comes from area 8. It grows stronger as creatures approach but it is never louder than a raspy whisper.
| RANDOM EVENTS d6 | Details |
| 1 | The gibbering from area 8 intensifies and affects a character. It functions like the confusion spell (lasts 1 crawling round). |
| 2 | A group of six deep ones teleports into the dungeon in area 2. They haul two merfolk prisoners to sacrifice them to the Core of Madness. The deep ones attack the characters on sight. If untied and healed, the merfolks may aid the characters in return. |
| 3 | A trip wire (DC 13 WIS) causes boulders to rain on the characters, dealing 2d6 damage (DC 13 DEX). |
| 4 | A magical pulse traverses the entire dungeon. The characters’ light sources are extinguished. |
| 5 | The characters experience a vision of a gargantuan being. Dozens of slithering tentacles emerge from an ineffable core that cannot be understood by mortal minds. The vision causes a headache that impedes spellcasting for 1 crawling round (DC 12 CON). |
| 6 | Acid drips from above. A character takes 1d8 damage unless they move out of the way fast (DC 12 DEX). |
1. Entrance Hall
Magical devices illuminate this chamber. A herring fish sigil decorates the walls. An educated scholar knows this is the seal of the deep ones, an elusive fish-folk society (DC 15 INT check). There is water erosion on all surfaces, markings from past floods (DC 13 INT check).
2. The Obelisk
A 30-foot-tall obelisk dominates this chamber. A detect magic spell reveals a strong magical aura and teleportation sigils along its surface. Focusing the spell on the strange obelisk for 1 crawling round reveals that it was used for teleportation within the last day.
- Steel Vases. The containers in the alcoves contain the bones of dozens of victims. A scholar or healer identifies the bones as the remains of merfolks (DC 13 INT).
3. Chapel of the Sea
Three fish-folk sit in prayer before a stone shrine littered with strange tomes and scrolls.
- The Believers. Three deep ones pray before visiting area 8. They are surprised at the characters’ appearance and attempt to capture them for future ritual sacrifices. One of them wields a coral scepter and is a Priest of the Core, with the power to summon a lesser water elemental to aid them (summon extraplanar).
- documents. The tomes and scrolls are fashioned from water-resistant materials like algae sheets and the flayed skin of some maritime creatures. The squirming Merran script is made with metallic inks. Translating this material for 1 crawling round reveals general lore about the deep ones and the Core of Madness’s presence.
- Treasure (6 XP). Among the documents, there is a Tome of Hadebe and two potions of giant strength.
4. Maritime Menageries
Five stone, coffin-like structures line the walls of this chamber. Faint vapor trails emerge from the lids.
The containers in each of the chambers labeled area 4 are filled with seawater. Each contains a selection of deep sea creatures like blind anglerfish, oarfish, and dark seafloor vegetation. The fish are harmless; their only utility is to amuse the deep ones that keep them here.
5. Secret Vault and Passages
The half-collapsed vault and the meandering passageway connect areas 4 and 8. In both areas, the hidden passage to this secret area can be found by exploring the wall for 1 crawling round. Approaching area 8 from here allows the party to surprise the Core of Madness.
- Treasure (8 XP). The stone coffers contain 700 gp, 1,900 sp, a +1 spear, two potions of healing, a bag of devouring, and a set of plate mail in need of repair.
6. Circle of Welcome
The Merran runes on the stone circle speak of an ancient deep one prayer that visitors must utter in respect to the Core of Madness. It is difficult to enunciate with human tongues (DC 14 DEX). If a character performs it, they have advantage on all checks when confronting the nightmarish being in area 8. Those who refuse are prioritized targets by the Core of Madness in area 8.
7. The Grim Ossuary
The remains of countless merfolks litter the rough floor of this chamber; a testament to the nefarious rituals that the deep ones have conducted for centuries. A scarab swarm emerges to attack at the sight of the characters.
8. The Core of Madness
A wicked calamity of thick, tentacles emerges from a gate-like wall as dark as night. They dance to unheard rhythms toward a bright, purple-light beacon.
The Core of Madness (kraken) is an otherworldly being beyond the comprehension of mortals. Performing the prayer in area 6 and surprising the avatar from area 5 are valid strategies to tilt the battle in the party’s favor. In a dramatic turn of events, throwing the bag of devouring (see area 5) at the monster causes a vortex. Both the avatar and the bag are destroyed, bypassing the encounter.
The avatar is not mobile and cannot pursue the party if they flee. If the being is defeated, it retracts into the dark core on the wall and shall not emerge for hundreds of years. Thus, the characters earn the deep ones’ enmity.
- The Beacon. The odd, magical brazier is meant to attract the core’s attention while being slightly out of reach. Even the deep ones have perished when underestimating the Core of Madness, hence the precaution.
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