Battlemap
Maelstrom Chainwreck
Chains, storms, and sacrificial decks hold back the thing below, if only for a little longer.
This dungeon is a shattered chain of boat-like platforms circling a roaring maelstrom, built from wrecked hulls, temple timbers, and stolen naval rigging. The party must cross unstable decks, solve tide-fed mechanisms, and recover relics needed to survive the descent beneath the waves, where an abyssal horror waits.
The air is wet with salt, blood, and ozone. Planks groan underfoot while the whirlpool below hammers the hulls with constant thunder, and every lantern flame burns blue in the storm wind. Distant whale-song and the clatter of chains drift through the maze of decks like warnings.
☠ Threat
An abyssal leviathan has learned to pulse through the whirlpool from below, sending serpents, drowned dead, and crushing pressure up into the platform maze. A surface-haunting guardian patrols the decks, while a deeper sea stalker guards the submerged approach, both drawn to any attempt to gather the relics needed for the final dive.
History
Long ago, a naval outpost and tide-temple were fused onto a wreck-strewn ring of hulls to monitor a sea route cursed by disappearances. When the abyssal creature began taking ships, the crew of the Black Chain repurposed the site into a lure and prison, chaining platforms around a central anchor-stone and feeding victims into the storm in hopes of controlling the monster below. They failed, but their wards still keep the ruins afloat.
Encounter Table
CRSalt-crazed sailors with water in their lungs drift between decks, moaning warnings and attacking anything that smells alive.
A sleek eel-like horror slips through flooded seams and snaps at exposed limbs before vanishing into the spray.
Barnacle-armored cult remnants patrol in pairs, searching for relics and trying to raise alarms with shell whistles.
A smaller abyss spawn hunts by vibration, slithering along the underside of platforms and striking from below.
Rumours & Whispers
The whirlpool was once a holy gate, and the crew chained themselves here so something below would not escape.
A drowned priest still rings a bell in the storm, and anyone who hears it too clearly is marked for the deep.
Two relics are said to be needed to open the way under the waves, one from a captain and one from a shrine.
Fishermen swear the broken decks move at night, retying their own ropes to lure new victims.
The creature beneath the maelstrom is not sleeping, only waiting for the right sacrifice.
Quest Hooks
Quest giver: Harbor Master Vessa
A coastal town's fishing fleet vanished after following a lantern signal found drifting from the whirlpool, and the families pay for answers or survivors.
200 gp and a blessing charm that grants advantage on one sea crossing or swim check
Quest giver: Archivist Pell
A temple archivist needs relic rubbings from the drowned chapel to prove the Black Chain once bound an abyssal entity rather than worshipped it.
A rare spell scroll and temple favor
Quest giver: Dockside fortune-teller Mara
Sailors whisper that the maelstrom opens briefly each night and reveals a route to a submerged vault if someone can survive the decks long enough to dive.
One magic item from the vault and a cache of pearls
Quest giver: Captain Orin Bale
A rival crew wants the central anchor-stone destroyed before it draws something worse from the deep.
300 gp and a share in salvage rights
Corridor Notes
Rope bridges sway between hull-sections, each one slick with spray and patched with old netting.
Barnacle-crusted chain rails run along the outer edges, keeping the platforms from being dragged into the vortex by anchoring them to a hidden central keel.
Broken prayer bells hung from mast fragments ring whenever a heavy step lands, alerting nearby guardians.
Pressure-release grates vent cold seawater in sudden bursts, briefly revealing submerged carvings and hidden markings on the floorboards.
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