Campaign Overview

Echoes of Atlantium

A generation ago, the majestic port city of Atlantium vanished in a single, silent tidal wave, swallowed whole by the ocean’s depths. To surface dwellers, it became legend, its fate whispered in taverns and coastal shrines, a cautionary tale of hubris and forgotten magic. But when the moon is new, sailors swear they see ghostly towers on the horizon, reëmerging like a mirage before sinking again into the abyss. Now, Lady Serin Ormance—the last scion of Atlantium’s noble line—offers a desperate plea: lead a salvage expedition to the sunken ruins, recover her family’s legacy, and uncover the arcane catastrophe that doomed a kingdom before it can be unleashed upon the world again.

Players begin in Brinehaven, a storm-battered frontier town of salt-caked docks, raucous taverns, and humble shrines to the Sea Mother. Here they will gather provisions, earn the trust of rival guilds, and navigate smuggler’s tunnels beneath the cliffs. Underwater environments—glowing kelp forests, ghostly shipwrecks, and labyrinthine caverns—test divers’ courage as they salvage Atlantium’s scattered relics. Along the way, they must parley with the Merfolk Court, whose regal rulers see Atlantium’s return as both threat and opportunity, and unravel the schemes of a fanatical cult that worships the Drowned King. Ancient tomes in submerged archives, bioluminescent algae puzzles, and elemental guardians stand between the adventurers and the city’s central secret: the Heart of Atlantium, an eldritch gem that once powered the city’s tidal wards.

The campaign’s main quest unfolds in five epic chapters. From Lady Serin’s first plea and the perilous salvage of a sunken merchant vessel, to diplomatic missions in the Kelp Forest Enclave, cleansing a renegade sea temple, and the final confrontation in Atlantium’s Grand Plaza, each stage builds toward a climactic choice: destroy the Heart and doom the lost city forever, or seal it and bind King Alaric’s spirit as a guardian of the deep. Dozens of side quests—ranging from ghostly rescues and ritual vigils to underwater puzzle-dungeons—enrich the journey, offering powerful magic items, faction alliances, and hidden lore.

This campaign blends high-stakes underwater exploration, political intrigue between surface and sea, haunting ghost stories, and elemental magic. It challenges players to balance diplomacy with combat, solve environmental puzzles, and make choices that will shape the fate of two worlds. Will you brave the unseen depths, earn the depths’ trust, and rewrite the destiny of a vanished empire? The echoes of Atlantium beckon—dive in, if you dare.

Starting Location

Brinehaven Coast

Brinehaven Coast is a bustling maritime frontier town perched on jagged cliffs overlooking the open ocean. Whitewashed stone buildings, salt-chapped and wind-beaten, fan out from a busy harbor where fishing skiffs and merchant vessels jostle for space. Crimson flags bearing a sea serpent billow above warehouses full of salted cod, exotic spices, and crates of finely worked coral jewelry. Narrow alleys wind between taverns and supply shops catering to adventurers, divers, and prospectors hoping to catch sight of Atlantium’s phantom spires on a moonless night. To the north, low dunes and tide pools studded with barnacles give way to hidden caves, rumored both sacred and haunted by the drowned. Along the shore, weathered stone markers etched with tide warnings stand beside shrines to the Sea Mother, where fishermen pray for safe passage. Evenings bring lantern-lit revelry at the Sea Shanty Tavern, where shanties and tall tales mingle with the scent of brine and roasted octopus. Yet beneath this vibrant surface lies tension: salvage crews warily eye one another, harbor guards watch for smugglers, and local priests whisper of an ancient curse tied to Atlantium’s return. Every new moon, when the tide slinks out and the sea stills, folk claim to glimpse ghostly towers shimmering on the horizon—enough to lure daring souls into renting diving suits, stocking provisions, and sailing out under dark skies in search of fortunes—or doom. Just beyond Brinehaven’s outer docks, the treacherous Underrock Cavern yawns like a great maw in the cliff face. Kelp-draped stalactites guard its entrance, and phosphorescent algae smear its walls with eerie green luminescence. Tidal currents swirl within, threatening to trap the unwary in hidden snags or drag them into underwater chasms. Locals say this cave was once a smugglers’ refuge, and its winding tunnels lead to secret grottos beneath the town. Occasionally, a diver emerges clutching a fragment of Atlantium pottery or a rusted bronze coin stamped with a serpent emblem—proof enough, they say, that the lost city still yields bounty to the brave. Still, old mariners tell stories of ghost sailors who patrol the cavern’s depths, their hollow eyes burning with vengeance. Many a would-be explorer has vanished within its walls, leaving only disturbed sand and rippled echoes behind.

Secrets

  • Smuggler’s tunnel beneath Sunward Docks leads to an underwater hatch.
  • Secret ledger in Sea Shanty Tavern lists recurring Atlantium sightings.
  • Lighthouse keeper communed with an otherworldly sea spirit.

Key Locations

Lighthouse of Tides

A stark white tower crowned with a brass lantern room that beams across the waves. Built on a rocky spur, the lighthouse warns ships of jagged reefs and shallow shoals. Each morning, the keeper rings a bell and refills the lamp’s oil reservoir. The interior spiral staircase is slick with saltwater spray, and walls bear protective wards against sea spirits. From the top, one can scan the horizon for Atlantium’s silhouette—at times so clear it appears to float atop the waves

Additional Notes

Keeper’s journal (hidden under the oil cans) hints at nightly rituals performed to calm the sea’s restlessness.

Underrock Cavern

A yawning grotto carved into the cliffside by centuries of pounding tides. Massive stalactites hang draped in kelp, and slick stones glisten with trapped water. Bioluminescent algae cast flickering green light over submerged tunnels that plunge into watery darkness. Diver’s supports—rusted anchors and broken flotsam—mark the cavern floor. Whispers echo from unseen chambers, and currents tug toward hidden chasms. Many who enter speak of uncanny sensations, as if watched by unseen eyes

Additional Notes

One tunnel leads to a sealed chamber with Atlantium-style relief work. The seal can be broken by chanting the Sea Mother’s hymn.

Shrine of the Moonlit Depths

A small open-air sanctuary carved from limestone. Beneath a crescent-moon arch, a basin of cool seawater reflects lantern light. Coraline statutes depict a hooded figure holding a trident. Offering bowls hold shells, coins, and bits of sea glass. Priests of the Sea Mother perform nightly vigils here, praying for lost souls and safe voyages. Tides lap at the shrine’s base, and on nights of the new moon, reflections dance like phantoms on the stone floor

Additional Notes

A false panel behind the main statue reveals an ancient Atlantium gem—one of four keys to the royal vault.

Sunward Docks

A sprawling wooden pier lined with creaking merchant ships, fishing boats, and salvage barges. Massive barrels of salted fish, crates of exotic shells, and coils of rope sit under tarpaulin awnings. Sailors shout orders as stevedores heave cargo, while deckhands tie off lines and scrub barnacle-encrusted hulls. Lanterns hang from rigging, flickering against the damp wood. From here, one can hire a weathered cutter or join a salvage crew venturing to Atlantium’s reappearing ruins

Additional Notes

Pier schedule changes weekly. A secret trapdoor underneath a loose board leads to a smugglers’ tunnel that runs beneath the town.

Sea Shanty Tavern

A timbered two-story tavern thick with salt and ale. A grand mast crossbeam supports a single chandelier of driftwood and conch shells. Roughhewn tables bear rings of spilled mead, and the air thrums with sailors’ songs and tall tales of ghostly towers. Behind the bar, barrels of spiced rum and brine-cured duck hang from iron hooks. A low stage hosts wandering bards at night, while bounty posters flutter near the hearth, offering gold for Atlantium salvage finds

Additional Notes

A hidden compartment beneath the bar stores disputed salvage papers and a fragment of Atlantium’s royal seal.

Thalassian Depths

The Thalassian Depths encompass a vast underwater realm of sunken spires, coral forests, and half-buried ruins that once formed Atlantium’s outer districts. Phosphorescent corals bloom in kaleidoscopic colors, illuminating labyrinthine kelp groves where schools of silverfish dart like living lanterns. Weathered stone pylons, carved with Atlantium’s serpent-sigil, protrude through shifting sand drifts, marking ancient avenues now claimed by octopuses and eel-folk. Beneath twisting arches, tidal currents ebb and flow with unnatural rhythm, sometimes pulling intrepid divers toward hidden grottoes guarded by merfolk sentries. Bioluminescent jellyfish pulse in hypnotic patterns along cavern ceilings, and at deeper depths, hydrothermal vents cast cloud-white plumes into the gloom. Shipwrecks form treacherous reefs, their iron hulls encrusted with barnacles and half-submerged in silt. Predatory reef sharks patrol the darker trenches, while bioluminescent anglerfish lunge at unwary explorers. A half-collapsed pylon hints at the threshold to Atlantium’s inner sanctums. Many who traverse these depths find Atlantium artifacts—bronze fragments, coral-inlaid pottery, and arcane glyphs—but rumors persist that a territorial merfolk court now claims this realm as sovereign. Negotiating safe passage requires delicate diplomacy—or daring stealth.

Secrets

  • A merfolk noble hides Atlantium relics within coral chests beneath the enclave.
  • Reef currents conceal a hidden tunnel to Atlantium’s outer wall.
  • Ghostly Atlantean psalms can be heard in the Cavern of the Drowned.

Key Locations

Kelp Forest Enclave

A dense underwater forest where towering kelp fronds sway like cathedral columns. Hidden among the stalks are woven platforms of driftwood and shell, suspended on current. Merfolk guards patrol the enclave’s perimeter, their spears fashioned from shark teeth and coral. Pearlescent lanterns hang from kelp ropes, casting dappled light over colorful anemones. Schools of neon parrotfish flit through passageways, and octopus scouts monitor intruders with cautious curiosity. Murals carved into basalt boulders depict Atlantium’s founding, hinting at alliances long dissolved

Additional Notes

Sentries speak Atlantean dialect; persuasion checks allow safe passage. A hidden grotto beneath a tangled thicket houses a stolen Atlantium artifact.

Reef of Whispers

A broad coral plateau dotted with heaving mounds of rose-tinted coral, resembling sleeping giants beneath the waves. Whispering currents pass through narrow channels, generating soft tones like distant voices. Divers report hearing Atlantium prayers or warnings. At the reef’s heart stands a collapsed tower with an intact spiral staircase, leading to a submerged guardroom filled with rusted weapons and shattered banners. A colossal clam clings to the summit, rumored to guard a pearlescent treasure

Additional Notes

Lingering echoes grant advantage on passive Perception for secret alcoves. Removing the clam’s shell yields a rare pearl key fragment.

Cavern of the Drowned

A shadowy cavern whose entrance is veiled by a curtain of luminescent jellyfish. Inside, the water is chillingly still, and spectral lights drift through darkness. Stalactites hang overhead, dripping mineral-rich water into jade pools. Beneath the surface, skeletons of former explorers lie scattered, their armor fused with kelp. A submerged altar carved in Atlantium style holds offerings—coins, coral figurines, and rusted keys. Guardians of barnacle-armored swordfish patrol the entrance, defending the sanctity of this drowned temple

Additional Notes

The altar’s offerings activate a hidden door when arranged correctly (DC 15 Intelligence check). Swordfish attacks can be evaded with stealth DC 14.

Sunken Citadel of Atlantium

The Sunken Citadel is the drowned heart of the lost city, lying forty fathoms below the ocean’s surface. Massive stone walls carved with serpentine motifs enclose coral-encrusted ramparts and collapsed archways. Grand columns, once gleaming white, now teeter amid swirling schools of fish, and broken statues of Atlantium’s founders lie half-buried in silt. Bioluminescent algae spills from cracks, illuminating murals that depict the city’s rise and cataclysmic fall in glowing blues and greens. Canals that once carried gondolas are now narrow trenches lined with barnacles and seaweed. The palace gates have been pried open, and frozen statues of guards stand as silent sentries. At its center, the Grand Plaza stretches, with an ornate fountain at its core—its basin now home to a giant clam that churns with ritual energy. Beyond lie the Royal Archives, The Sundered Spire, and the Throne Room—where Atlantium’s last ritual unleashed a tidal cataclysm that swallowed the city whole. Strange currents swirl in unnatural patterns, and echoes of Atlantean chants drift through broken halls. Those who explore must confront drowned undead, corrupted water elementals, and the restless spirit of King Alaric before they can claim the city’s hidden treasures and ancient powers.

Secrets

  • A hidden vault under the Throne Room holds Atlantium’s crown and one final key fragment.
  • Royal Archives contain references to a surviving heir hidden on the surface.
  • The Heart of Atlantium can be harnessed to summon a tidal avatar.

Key Locations

Grand Plaza

Covering an area the size of three football fields, the Grand Plaza was once the civic heart of Atlantium. Now, seaweed chokes the mosaic floor, and barnacles encrust broken benches. A shattered fountain at its center still bubbles with enchanted water that glows faint green. Statues of heroic Atlantean figures stand jaggedly, and schools of fish dart through open archways. Tidal currents swirl unpredictably here, pulling divers toward hidden traps in the plaza’s edges

Additional Notes

Central fountain water grants water breathing for 1 minute if sipped carefully. Hidden pressure plate opens a secret tunnel beneath the plaza floor.

Royal Archives

A vaulted chamber lined with waterlogged scrollcases and coral-coated tomes. Atlantean librarians once cataloged spells of sea magic here; now ink runs and pages disintegrate in acidic water pockets. Shelves carved from luminescent stone display bronze tablets and crystalline orbs. A lectern holds the Tidekeeper’s Codex—sealed in a protective crystal globe—and contains the ritual that caused Atlantium’s demise

Additional Notes

Codex can be removed with a DC 18 Strength check. Tampering triggers a minor elemental shield.

The Sundered Spire

A towering column cracked in two, rising from the city’s depths like a jagged beacon. Climbing its fractured walls through ankle-deep silt leads to a chamber that houses the Heart of Atlantium—a gem pulsing with eldritch energy. Surrounding it are broken magical conduits that once regulated the city’s tidal wards. The spire hums with residual power, and its walls are etched with Atlantean runes warning of catastrophe

Additional Notes

Heart of Atlantium must be approached carefully; wards still active. A locked door at the apex opens only with all four key fragments.

NPCs in Brinehaven Coast

Lady Serin Ormance

A composed noblewoman in widow’s black lace, scarred by loss but determined. She clutches an ornate conch shell at her waist.

Role: Quest Giver Other Details: Last scion of Atlantium’s ruling house, seeking to salvage her family’s legacy.

Captain Garrick Thorne

A grizzled sea captain with salt-white hair and a missing eye covered by a patch.

Role: Salvage Guildmaster Other Details: Controls diving permits; rumor says he’ll double-cross unwary divers.

Tobin Saltbeard

An elderly mariner whose long, curly beard is flecked with sea salt and small shells.

Role: Local Storyteller Other Details: Claims to have seen Atlantium’s towers reemerge; offers cryptic warnings.

Xyra Waveborn

A mysterious fortune-teller draped in kelp-green silks, her eyes reflecting candlelight like stormy seas.

Role: Soothsayer Other Details: Her trinkets supposedly amplify underwater detection; she demands rare coral shards in payment.

Brother Malcus

A solemn priest of the Sea Mother, robed in water-stained vestments embroidered with wave motifs.

Role: Shrine Keeper Other Details: Holds lore of Atlantium’s divine patron and the lost city’s cataclysmic ritual.

NPCs in Thalassian Depths

Queen Nerissa Tideweaver

A regal merfolk monarch with cobalt-blue scales and flowing silver hair, draped in seaweed silks.

Role: Merfolk Ruler Other Details: Seeks to protect her people’s domain but open to alliance against common threats.

Lord K'haur Stormspear

A triton warlord bearing a barbed trident and bearing numerous scars from deep-sea clashes.

Role: Trident Guard Commander Other Details: Suspicious of surface dwellers; demands proof of loyalty before granting passage.

Captain Ashvale’s Shade

The ghostly echo of a pirate captain, bound to his sunken galleon’s wreckage.

Role: Wandering Apparition Other Details: Offers cryptic warnings in exchange for releasing him from his eternal haunt.

NPCs in Sunken Citadel of Atlantium

Lia, Naiad Guide

A water spirit bound to Atlantium’s fountains, her hair drifting like seaweed and eyes glowing turquoise.

Role: Reluctant Ally Other Details: Offers guidance through the spire but demands a favor in return.

King Alaric’s Shade

The restless spirit of Atlantium’s final ruler, clad in corroded armor and bearing a spectral trident.

Role: Final Antagonist Other Details: Driven mad by the cataclysm, he seeks to complete the ritual and reclaim life.

Oracle Thalassa

A deep-sea oracle with translucent skin, veins pulsing with bioluminescence, speaking in riddles.

Role: Lorekeeper Other Details: Knows the true name of the Heart’s warding spells and how to break them.

Factions

Brinehaven Salvage Consortium

The Brinehaven Salvage Consortium is a powerful guild of shipowners, divers, and investors who control most salvage operations along the coast. They maintain rigorous permits, tariffs, and insider knowledge of underwater hazards. Their banner—a jangling anchor over crossed harpoons—floods every harbor with their colors, and their armed cutters patrol shipping lanes.

Goals

  • Monopolize Atlantium salvage rights.
  • Acquire Atlantean technology for surface trade.
  • Suppress competing crews.

Relationships

With Other Factions
They clash with the Merfolk Court over territorial rights and have uneasy truces with the Cult of the Drowned King, occasionally trading artifacts for forbidden lore.
With Players
They may hire or hinder the party depending on how threatened they feel. Gaining their favor ensures safe harbor; crossing them invites ambushes and blacklists.

Merfolk Court of Nerissa

The Merfolk Court of Nerissa rules the Thalassian Depths with regal dignity. Queen Nerissa Tideweaver presides over a council of nobles, priests, and warlords. Their coral palaces and seaweed halls teem with aquatic crafts and diplomatic intrigue. They strive to preserve their ancestral waters from exploitation, believing Atlantium’s return threatens the ocean’s balance.

Goals

  • Guard Atlantium’s ruins from desecration.
  • Reclaim Atlantean artifacts to strengthen sea-magic.
  • Form alliances with surface dwellers against deeper threats.

Relationships

With Other Factions
They are wary of the Salvage Consortium’s encroachment and view the Cult of the Drowned King as a heretical splinter undermining oceanic harmony.
With Players
They will aid or oppose the party based on proven respect for the sea. Diplomatic success grants safe conduct; deceit or plunder results in banishment or combat.

Cult of the Drowned King

The Cult of the Drowned King worships the spirit of King Alaric as a divine avatar of the sea’s destructive force. Its fanatics serve underwater shrines, offering sacrifices to hasten Atlantium’s rise. They conceal their rituals beneath coral altars and lure surface cultists with promises of power over ocean currents.

Goals

  • Unleash Atlantium’s cataclysm once more.
  • Recruit surface agents to gather ritual components.
  • Sow chaos in coastal cities as preludes to the cataclysm.

Relationships

With Other Factions
They operate in secret, undermining both the Salvage Consortium and the Merfolk Court. Occasionally they trade stolen Atlantean relics for forbidden knowledge.
With Players
They view the party as obstacles or potential converts. Cultists may ambush or infiltrate their ranks; saving a cultist might yield critical intelligence about the final ritual.

Main Questline

A Noble’s Plea

Given by: Lady Serin Ormance

Lady Serin invites the party to Brinehaven, revealing her lineage and pleading for skilled adventurers to recover Atlantium’s lost treasures. She provides partial maps and funds to purchase diving gear, warning that time is short before tidal cycles erase the ruins entirely. The party must first gather supplies, recruit a trustworthy crew, and chart a safe route through Underrock Cavern near the coastline.

Goals

Secure gear, assemble a crew, and navigate Underrock Cavern to reach open water.

Reward

  • 250 XP
  • Diving Bell of Safe Descent (grants 60 ft underwater breath)
  • Partial Atlantium map fragment

Secrets

  • The map fragment conceals a second layer of hidden runes.
  • Lady Serin’s true aim is finding the Heart of Atlantium.

DM Notes

Emphasize investigative roleplay in Brinehaven and environmental hazards in the cavern.

Into the Deep

Given by: Captain Garrick Thorne

With equipment in hand, the party joins Captain Thorne’s salvage barge and descends to Atlantium’s outskirts. Their task is to recover a sunken merchant vessel rumored to contain Atlantium-made bronze ingots. Divers must clear away barnacles, avoid razor-jawed crabs, and fight off sahuagin patrols. Within the wreck’s hold lies a sealed crate inscribed with Atlantean glyphs—inside, a bronze coil that hums with arcane energy.

Goals

Recover the inscribed bronze coil and return it intact to the surface.

Reward

  • 400 XP
  • Coil of Atlantium Bronze (+1 to Strength checks underwater)
  • Captain Thorne’s begrudging respect

Secrets

  • The coil is part of a larger Atlantium apparatus.
  • Sahuagin know more about Atlantium’s fall but demand tribute.

DM Notes

Include 2 sahuagin ambush encounters; allow creative use of coil’s magic.

Whispers of the Merfolk

Given by: Queen Nerissa Tideweaver

Having gained merfolk escort, the party is brought to the Kelp Forest Enclave for parley. Queen Nerissa distrusts surface dwellers but is open to alliance if the adventurers retrieve her stolen royal scepter, pilfered by a rogue triton band. The rescue mission leads through labyrinthine kelp corridors, requiring stealth, negotiation, or combat. Finding the triton lair reveals evidence of a deeper plot to harness Atlantium’s Heart.

Goals

Recover Queen Nerissa’s scepter and return it safely for formal alliance.

Reward

  • 500 XP
  • Ring of Water Breathing
  • Merfolk alliance (aid in future encounters)

Secrets

  • Rogue tritons serve a hidden commander near the Citadel.
  • The scepter holds one of four key fragments.

DM Notes

Allow diplomacy path granting information; combat path yields extra triton gear.

Temple of Tides

Given by: Brother Malcus

Brother Malcus learns of an underwater shrine to a renegade sea god near Atlantium’s eastern wall. This Temple of Tides once anchored the city’s water wards, but now a naga priestess twists its magic. The party must infiltrate the temple, solve a water-flow puzzle, and defeat the priestess and her water elementals. Restoring the shrine strengthens the wards surrounding Atlantium and reveals a hidden passage toward the Sunken Citadel.

Goals

Purify the Temple of Tides and reclaim the ritual altar.

Reward

  • 600 XP
  • Trident of Tidal Command
  • Knowledge of secret Citadel entrance

Secrets

  • Priestess’s ritual journals describe a planned second cataclysm.
  • Temple maps indicate a shortcut to the Western Gate.

DM Notes

Include environmental puzzle with redirected water jets; boss fight in flooded sanctum.

Echoes of the Cataclysm

Given by: Oracle Thalassa

Entering Atlantium’s Grand Plaza, the party confronts the restless spirit of King Alaric in the Royal Archives. Thalassa warns that the Heart of Atlantium, still pulsing in the Sundered Spire, threatens to repeat the cataclysm. The adventurers must navigate collapsing halls, banish undead librarians, and retrieve the Tidekeeper’s Codex. With the codex’s secrets, they can breach the spire, confront Alaric’s shade, and decide whether to destroy or seal the Heart forever.

Goals

Recover the codex, confront King Alaric’s shade, and neutralize the Heart.

Reward

  • 800 XP
  • Shard of the Heart (attunement required)
  • Blessing to calm the seas (long-term campaign boon)

Secrets

  • Destroying the Heart scatters Atlantium fragments into the ocean.
  • Sealing it binds King Alaric’s spirit to a new guardian.

DM Notes

Final encounter stages: Archives skirmish, spire ascent, boss fight at Heart chamber.

Side Quests in Brinehaven Coast

The Diver’s Debt

Given by: Captain Garrick Thorne

Captain Thorne needs someone to recover a sunken ledger chest from Underrock Cavern. The chest belonged to his late first mate and contains navigational charts vital to precise Atlantium mapping. Thorne warns that shifting currents and kelp tangles make the cavern treacherous. Divers must contend with narrow passages, sudden surges, and rumored cave-dwelling horrors. Success will gain Thorne’s trust—and a promise of discounted salvage fees.

Goals

Retrieve the ledger chest and return it to Captain Thorne in one piece.

Reward

  • 150 XP
  • Discounted salvage permit
  • Captain’s trust (advantage on one future negotiation)

Secrets

  • The chest also holds a torn page of an Atlantium ritual.
  • Thorne plans to claim any Atlantium artifacts for himself.

DM Notes

If players stall, Thorne commissions a second diver—rival NPC may complicate later salvage.

Echoes in the Kelp

Given by: Tobin Saltbeard

Old Tobin heard ghostly singing among the kelp forests offshore. He offers a silver coin if you can record or collect proof of the haunting. Divers must navigate dense kelp thickets, avoid razor-shaped fronds, and photograph submerged amphoras etched with Atlantium iconography. At the heart of the kelp bed lies a half-buried statue playing a silent chorus. Beware siren illusions and kelpie ambushes.

Goals

Document the kelp forest singing and retrieve the statue’s hidden fragment.

Reward

  • 100 XP
  • Silver coin from Tobin
  • A vial of bioluminescent algae (useful as underwater light source)

Secrets

  • The statue conceals a hidden Atlantium-style key fragment.
  • Tobin once dabbled in illicit treasure sales.

DM Notes

Siren illusions can charm unless players succeed on DC 14 Wisdom saves.

Shrine Vigil

Given by: Brother Malcus

The Shrine of the Moonlit Depths requires a nightly vigil to appease restless sea spirits. Brother Malcus asks adventurers to stand watch and fend off minor elementals drawn by the shrine’s power. Participants must light protective ward candles, recite ancient prayers, and intercept ghostly wisps before they overwhelm the sanctuary. This ritual reinforces the protective ward around Brinehaven and stabilizes offshore currents.

Goals

Maintain the shrine’s wards through the entire night without letting more than three wisps escape.

Reward

  • 120 XP
  • Blessing of the Sea Mother (one reroll on water checks)
  • Holy water flavored with salt

Secrets

  • One of the candles is forged from Atlantium silver.
  • Repeated vigils gradually weaken a ward protecting an Atlantium vault.

DM Notes

Use 5 minor water elementals as opponents; allow roleplay for prayer sequences.

Smuggler’s Bargain

Given by: Madam Xyra Waveborn

Xyra needs a rare black pearl from a sunken merchant’s hold near the reef. In exchange, she offers a prophecy about Atlantium’s fate. The wreck sits at twenty feet below surface and is infested with reef sharks and giant crabs. Divers must pry open a barnacle-sealed hatch to retrieve the pearl. Xyra warns the pearl pulses with faint magic and may attract otherworldly attention.

Goals

Retrieve the black pearl intact from the merchant wreck and deliver it to Xyra.

Reward

  • 130 XP
  • Prophecy revealing next main quest clue
  • Temporary advantage on Insight checks for one hour

Secrets

  • The pearl is one of four keys to the Moonlit Shrine.
  • Xyra plans to shatter the pearl for power.

DM Notes

Shark and crab stats should challenge a 2nd‐level party; stagger attacks to build tension.

Repel the Raiders

Given by: Council of Brinehaven

A fleet of coastal raiders has begun attacking Brinehaven’s fishing boats at dawn. The town council tasks you with organizing defenses and leading a counter-raid. Players can repair harbor chains, set up ballistae, or board enemy longboats. Raiding pirate sergeants are well-armed but disorganized. Defeating them will secure passage for salvage crews and earn goodwill with townsfolk.

Goals

Protect incoming fishing vessels and defeat the raiders in at least three skirmishes.

Reward

  • 200 XP
  • Free lodging in Brinehaven
  • 50 gp in town favors (access to an exclusive artisan merchant)

Secrets

  • Raiders took Atlantium-style bronze ingots to sell overseas.
  • Council members fear an inside accomplice.

DM Notes

Include two skirmish locations: outer docks and cliff lookout; allow players to rig traps.

Side Quests in Thalassian Depths

Gifts for the Queen

Given by: Queen Nerissa Tideweaver

To secure safe passage, the merfolk queen requests three rare items: a black pearl, a carved coral crown, and a vial of deep-sea ink. These gifts symbolize respect for merfolk traditions. Players must retrieve them from a shark-infested trench, an undersea fey grove, and a sunken merchant galleon. Each location poses unique hazards, from aggressive wildlife to shifting currents. Success will earn the queen’s favor—and a formal escort through merfolk waters

Goals

Collect all three gifts and present them to the queen in proper ceremony.

Reward

  • 200 XP
  • Merfolk escort through Thalassian Depths
  • Queen’s favor (advantage on one diplomacy check)

Secrets

  • Shark trench hides an Atlantean relic.
  • Coral crown is cursed with a minor water elemental.
  • Deep-sea ink reveals hidden Atlantean glyphs.

DM Notes

Allow varied approaches: stealth, combat, or diplomacy in each retrieval.

Echo Chamber Exploration

Given by: Captain Ashvale’s Shade

The ghostly captain yearns to explore his old shipwreck beneath the Reef of Whispers. He asks the party to navigate narrow corridors, confront barnacle-armored swordfish, and retrieve his captain’s log. The log holds secrets of a sabotage that sank his vessel—evidence of darker forces behind Atlantium’s fall. Facing poltergeist sailors and treacherous currents, players must decide whether to free the captain’s soul or use the log for leverage

Goals

Retrieve the captain’s log and return it to his Shade.

Reward

  • 180 XP
  • Captain’s spectral sword (ineffective out of water)
  • Knowledge of sabotage that aids main quest

Secrets

  • Log names a traitor within Atlantium’s court.
  • Spectral sword transforms into seaweed whip on land.

DM Notes

Use incorporeal pirate stats; emphasize eerie atmosphere.

Bioluminescent Bloom

Given by: Merfolk Scholar Tyriel

A young merfolk scholar seeks samples of rare bioluminescent algae that bloom only around hydrothermal vents. He needs three specimens, each glowing a different color. The vents are guarded by magma crabs and charged elemental vents that scald divers. Collecting samples safely demands protective gear or quick reflexes. Tyriel will use the algae to create a light spell for dark caverns

Goals

Retrieve three distinct algae specimens and deliver them alive to Tyriel.

Reward

  • 150 XP
  • Scroll of Faerie Fire (blue glow variant)
  • Tyriel’s gratitude (free translation of Atlantean texts)

Secrets

  • Algae glows pulsingly to mimic Atlantean distress signals.
  • Scholar hides an Atlantean glyph in his notes.

DM Notes

Magma crabs can be distracted by heat sources; allow creative solutions.

Side Quests in Sunken Citadel of Atlantium

Recover the Crown

Given by: Oracle Thalassa

Thalassa tasks the party with finding Atlantium’s ceremonial crown from a hidden vault beneath the Throne Room. The vault door is sealed by four key fragments scattered across the spire, archives, plaza, and outer wall. Players must solve Atlantean runic puzzles to unlock each fragment’s chamber, then reassemble the crown. But as they work, undead royal guards and water elementals converge to halt intruders

Goals

Assemble all key fragments, open the vault, and retrieve the crown.

Reward

  • 300 XP
  • Crown of Alaric (grants +1 AC underwater)
  • Access to final main quest

Secrets

  • One crown jewel is a false lead laced with a curse.
  • Thalassa withheld the vault’s true location initially.

DM Notes

Include 4 short puzzles (rune alignment, sequence memory, water flow redirection).

Archive Purge

Given by: Captain Garrick Thorne’s Shade

The ghost of Captain Thorne appears in the Royal Archives, demanding you purge corrupted tomes that threaten to spawn aquatic horrors. You must identify tainted volumes, burn them in a sanctified brazier, and survive waves of water weirds and book golems. Each destroyed tome stabilizes a ward in the Citadel, preventing further cataclysmic surges

Goals

Destroy at least five corrupted tomes and survive the resulting elemental backlash.

Reward

  • 250 XP
  • Tome of Water Shields
  • Reduced elemental resistance (ally assistance)

Secrets

  • One burned tome contained instructions for reversing the Heart’s activation.
  • The shade once sabotaged these archives before his death.

DM Notes

Use wave-based encounters; escalate difficulty as more tomes burn.

Spire Ascent

Given by: Lia, Naiad Guide

Lia demands you climb the Sundered Spire to seal ruptured magical conduits and prevent a final surge. Each conduit is guarded by a water elemental bound by Atlantean chains. You must dismantle the chains without collapsing the conduit structure, all while contending with shifting silt floors and sudden current surges. Success will empower Lia to protect Atlantium’s legacy

Goals

Seal three conduits atop the spire and survive the elemental counterattacks.

Reward

  • 350 XP
  • Lia’s blessing (water elemental ally, one use)
  • +2 on saving throws against water magic

Secrets

  • One conduit is deliberately sabotaged by an unknown betrayer.
  • Lia can bridge conduits to trap an elemental temporarily.

DM Notes

Each conduit room has a unique environmental hazard: collapsing steps, electric eels, pressure shifts.

Encounters

Reef Ambush

Medium

Suggested Level: 2-3

Sahuagin warriors lie in wait among coral spires to ambush passing divers.

Creatures

  • 3 Sahuagin
  • 1 Sahuagin Priest

Terrain Features

  • Dense coral pillars provide half cover.
  • Strong lateral current imposes disadvantage on ranged attacks.
  • Pockets of stinging sea urchins along the floor.

Treasure

50 gp worth of pearls and coral fragments; Sahuagin trident (+1 damage underwater).

DM Notes

Scale sahuagin numbers by party size; use current to herd players.

Ghost Ship Wreck

Hard

Suggested Level: 3-5

An abandoned merchant vessel haunted by spectral sailors rises at low currents.

Creatures

  • 4 Spectral Sailors
  • 1 Wraith Captain

Terrain Features

  • Rolling decks restrict movement (DC 12 Dexterity save to avoid slip).
  • Loose rigging overhead can be used to swing or entangle.
  • Leaking lanterns create zones of dim light.

Treasure

Rusted key to Atlantium vault; charts showing secret underwater passages.

DM Notes

Encourage creative use of ghost ship features; Wraith Captain fears divine light.

Trench Leviathan

Deadly

Suggested Level: 5-7

A young kraken’s tentacles and guardian sea spawn attack explorers near a deep trench.

Creatures

  • 2 Giant Kraken Tentacles
  • 1 Young Kraken Spawn

Terrain Features

  • Vertical dropoff forces grappling saves.
  • Low visibility silt clouds obscure vision.
  • Hydrothermal vents cause random area damage (1d6 fire per round).

Treasure

Kraken ink vial (grants invisibility underwater for 1 round); barnacle-encrusted gold coins.

DM Notes

Warn players of terrain; kraken spawn uses area entanglement attacks.

Currents of Madness

Medium

Suggested Level: 2-4

A collapsed Atlantean ward releases rogue water elementals that swirl unpredictably.

Creatures

  • 2 Water Elementals

Terrain Features

  • Erratic water jets push players (DC 13 Strength save) positioned randomly.
  • Submerged columns offer cover but may collapse.

Treasure

Elemental core (component for a custom water amulet); 75 gp in silver coins.

DM Notes

Use dynamic terrain shifts; elementals adapt tactics if outnumbered.

The Siren’s Song

Medium

Suggested Level: 4-6

A lone siren and her merrow guards lure divers into fatal traps with haunting melodies.

Creatures

  • 1 Siren
  • 2 Merrow

Terrain Features

  • Natural amphitheater of coral amplifies song.
  • Sharp coral shards impose difficult terrain.
  • Underwater current flows toward deadly beehive urchins.

Treasure

Siren’s voice harp string (+2 on charm saves); merrow harpoon spear.

DM Notes

Charm effects require Wisdom saves (DC 15); allow perception to locate hidden urchins.

Magic Items

Trident of Tidal Command

Very Rare
A coral-inlaid trident that can control local currents once per short rest.

Location

Temple of Tides

Attunement

True (requires 1 hour of communion with a water spirit)

Conch of the Sunken Beacon

Rare
A polished conch that emits a guiding light underwater, revealing hidden glyphs.

Location

Sunward Docks ledger chest

Attunement

False

Ring of Water Breathing

Uncommon
A silver band etched with wave motifs, allowing 10 minutes of water breathing once per day.

Location

Kelp Forest Enclave gift exchange

Attunement

False

Coral Dagger

Uncommon
A dagger forged from razor-sharp coral; deals +1 damage under water.

Location

Reef of Whispers

Attunement

False

Cloak of the Sea’s Embrace

Rare
A shimmering cloak that grants advantage on Stealth checks underwater.

Location

Smuggler’s Bargain haul

Attunement

True (must be submerged for 1 hour daily)

Scale of the Deep One

Uncommon
A single giant fish scale that grants resistance to cold damage.

Location

Cavern of the Drowned altar

Attunement

False

Amulet of Atlantium’s Legacy

Very Rare
An amulet housing a sliver of Atlantean gem; advantage on Arcana checks related to Atlantium.

Location

Royal Archives

Attunement

True (reads a passage from the Tidekeeper’s Codex)

Chart of the Vanished City

Rare
An animated map that updates nightly, showing Atlantium’s current position.

Location

Sea Shanty Tavern secret compartment

Attunement

False

Lantern of the Abyss

Uncommon
A brass lantern that sheds bright light only underwater, dispelling illusions.

Location

Shrine of the Moonlit Depths secret panel

Attunement

False

Heart Shard of Atlantium

Legendary
A glowing crystal fragment that can banish one summoned water elemental.

Location

Sundered Spire apex

Attunement

True (requires boon from Oracle Thalassa)

Player Characters

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