Secrets of the Sunken

The ocean floor is inhabited. Some of it wants to trade with you. Most of it does not.

Secrets of the Sunken turns the empty blue between islands into a place with residents, politics and predators. Coral villages sit on the seabed where merfolk traders deal in the things only the deep produces. A hostile people raid them from the lightless trenches. Older things lie half-buried between them, still guarded. And somewhere out in the dark water, something very large is waiting to be woken.

Every creature here breathes water, fights in three dimensions, and behaves differently from anything on land.

🐟 Over Fifty New Creatures

The swim between islands used to be a commute. It is now the most crowded part of the world.

More than 50 new sea creatures have been added, spread across reefs, kelp forests, open water and the deep. The shallows are busy and mostly indifferent to you. The further down you go, the less that holds.

🌿 New Sea Flora

The seabed has been replanted. Alongside vanilla kelp and seagrass there is a new range of underwater plant life, filling out reefs, basins and the slopes around merfolk settlements — so the floor reads as a habitat rather than a texture.

🔱 The Merfolk

Humanoid above the waist, fish below it. Merfolk are peaceful traders who live in coral domes on the ocean floor — and they are armed.

Right-click one to open a familiar merchant screen. The title tells you their rank:

Coral is nearly unfarmable without a warm ocean, so a Reefwarden who sells it is worth finding.

They fight back

Hurt a merfolk and it draws a trident. It throws from range, stabs up close, and every merfolk within 32 blocks joins in — attack one trader and the whole village turns on you. They stand down about fifteen seconds after the last threat is gone, and they won't haggle while their weapon is out.

They also hunt drowned on sight, meet Trench raiders head-on, and are sensible enough to run from a kraken.

Merfolk never drop their tridents, and the ones they throw can't be picked up. Killing traders is not a trident farm.

🏘️ Underwater Villages

Villages generate on the floor of any ocean biome, roughly 30 chunks apart, wherever there's enough open water and a reasonably flat basin.

They're built procedurally rather than stamped from a template, so every settlement shapes itself to the seabed it lands on:

• The Tide Hall — prismarine, four arched doorways, lantern-capped corner pillars and a stepped roof. Home to an elder and two attendants, and a loot chest worth opening.
• Coral domes — houses grown rather than built, each in one of five coral species, no two the same size, lit by a sea lantern at the crown.
• Kelp farms — tended beds of sand and dirt under standing kelp.
• Sea-lantern lampposts marking the paths between.
• The brazier — cold, unlit, standing at the centre of the village. Leave it that way. See below.

🏛️ Sunken Structures

The villages are the part of the ocean floor that's still lived in. They aren't the only thing down there.

New structures generate across the seabed, and they're built to be looted. The chests in them hold the kind of thing you don't get from trading.

Every one of them is defended. Whatever is guarding a structure was there long before you found it, and it does not consider the contents yours. Swim in expecting the fight, not the chest.

🦈 The Great White

The threat you'll actually meet. Fast, persistent, and far more interested in you than you'd like.

A great white doesn't simply swim at you:

• It charges. From four to fourteen blocks out it lunges, so backing off doesn't buy the space it looks like it should.
• It smells blood. Once its prey drops below 60% health it enters a frenzy — faster, harder-hitting, and visibly thrashing. That's your warning.
• It respects a hit to the snout. Strike it head-on as it comes in and it aborts the run, banks hard into a turn, sweeps out to your flank, and comes back in from the side. Hit it from behind and it just gets angry.
• It eats and leaves. A shark that makes a kill is full, and drifts off instead of turning to the next victim. Attack it and that courtesy ends immediately.

🐙 The Kraken (Boss)

You don't find a kraken any more. You call one.

A brazier stands unlit at the centre of every merfolk village. Light five of them and the kraken wakes. Nothing else summons it — it no longer spawns on its own, anywhere, at any depth.

Which means the deep ocean is now yours to explore in peace, right up until the moment you decide it shouldn't be. Like the Wither, this is a boss you opt into. Unlike the Wither, you have to travel to five separate villages to do it.

Once it's awake, it never despawns, and it does not leave.

Where the Wither is remembered for what it destroys, a kraken is remembered for who didn't come back. It never breaks a single block.

It moves at half the speed of a walking merfolk, and that is deliberate — a kraken cannot win a chase, so it never bothers having one.

• The grapple. It lashes a tentacle out to fourteen blocks, kills your momentum, and hauls you into reach. With all eight arms it seizes up to four victims at once. You do not escape a kraken by swimming away from it.
• The sweep. Every few seconds it thrashes every arm at once — eight blocks in all directions, no line of sight required, scattering everything nearby. This is what turns an attack on one merfolk into an attack on the village.
• Its melee drags. Being hit pulls you closer instead of knocking you clear.
• The ink. Below half health it blacks out the water. Anything caught inside loses track of what it was fighting, and players are left effectively blind.
• It knits itself back together if you disengage, so half-hearted attrition loses ground.
• Arrows barely bother it. Shooting one from a boat is not the answer; the fight belongs in the water beside it.

As you wear it down, it starts losing tentacles — eight when whole, down to three at the end. Fewer arms means a slower grapple and a weaker sweep. You can see how the fight is going by counting them.

🗡️ The Trench

Half-Atlantean and half something worse, the Trench are a hostile people from the deep ravines and sea caves. They raid merfolk settlements, and they will happily add you to the list.

They spawn only in genuine darkness — the floors of ravines, sea caves, the deepest basins — and they hate the light. Bright water slows them down, which quietly means a well-lit merfolk village is hard ground to raid. Those sea lanterns are not just decoration.

Two roles, both organised, both fighting as a unit — hurt one and the patrol answers:

• Trench Raider — 30 HP, closes to melee with an axe salvaged off a wreck. The common one.
• Trench Harpooner — 24 HP, hangs back and throws harpoons.

Six bloodlines

Every Trench is crossed with something, and it shows:

All of them carry an anglerfish lure arching over the face — the one thing every Trench has in common.

⚒️ Brinesteel

A new ore, brinesteel, generates in the seabed — the deep's own metal, and a reason to bring a pickaxe underwater.

Raw ore on its own is worthless, and a furnace is no use to you down here. Brinesteel is worked where it was born: find a hydrothermal vent on the ocean floor, feed it your ore, and it hands back forged brinesteel. There is no other way to make it, and it is the only thing the armour can be built from.

Vents are rare, but they don't hide. They generate at random across the open ocean rather than inside any structure, and they're obvious enough that you'll know one on sight — the problem is never recognising a vent, it's finding one at all.

So the chain is short and entirely underwater: mine the ore, find a vent, feed it, forge the set. Nothing about it happens on land.

Brinesteel armour

A full set gives you what no surface metal will: it only works while it's wet.

• Every piece does something different. Helmet, chestplate, leggings and boots each carry their own wet bonus, so mixing brinesteel into a set is a real decision rather than a shortfall.
• Wetness is on a timer. Leaving the water doesn't switch the set off — it starts drying. You get a window to fight on the shoreline, and then you're wearing ordinary plate.

Submerged, brinesteel is the best thing you can be wearing down there. Dry, it's just armour. Every other set in the game punishes you for going in the water. This one punishes you for staying out.

Which quietly rewrites how you fight everything above. A kraken, a great white, a Trench patrol in a lightless ravine, whatever is guarding the structures — those fights all happen in the one place your best armour is at its strongest.

💡 Notes

• Everything is vanilla-compatible. Merfolk use the standard merchant interface, vents take ore directly — no new UI to learn anywhere in the mod.
• Safe to add to an existing world — villages, structures and vents generate in newly explored chunks.
• Brinesteel is still getting a visual pass. The ore, vents and armour work; the textures and models just aren't finished yet. Function first, looks shortly after.

Built for 1.20.1 Forge.