World 7

World 7: Pressure Ocean

Pressure Ocean is world 7 of 10, in the expertise tier. Its rule is Oxygen. You open it with the Abyssal Pearl, made from the core of the World 6 boss (Your Double).

The whole world is sea. There is no dry land: you live, fight and mine under water, and the only way to breathe for long is a snorkel helmet.

At a glance

Tier	Expertise
Rule	Oxygen
Station	Abyssal Press
Boss	Pressure Leviathan (3027 health, 35.8 damage)
Core	Leviathan Core
People	Diver
Way in	Abyssal Pearl: 1 Double Core, 8 Unstable Alloy, 4 Inverted Crystal
Variants	Slack-Tide Ocean (calm), Crushing Ocean (wild)
Atmosphere	Deep blue water fog closing in at 40 blocks, bubbles rising everywhere
Biomes	Its own, with two lesser biomes at its edges: Coral Shelf (sand floor) and Black Trench (trench rock floor)
Surge	Crushing Current
Travelling merchant	Drifting Diver
New gear	Tide Harpoon

Opening the world

• Recipe of the Abyssal Pearl (Matrix Workbench, after the World 6 boss (Your Double) is defeated): 1 Double Core, 8 Unstable Alloy, 4 Inverted Crystal.
• Rite: Drop it into water at least 3 blocks deep. See The way into each world.
• Arrival: a diving chamber on the sea floor at the centre of your group's parcel: a glass dome full of air around the Threshold, with lanterns, a chest of supplies (4 Oxygen Capsules, 3 Apnea Kelp, an iron pickaxe) and a door facing south. Doors hold water back, so the chamber stays dry when you open it. An Air Vent bubbles on the floor a few strides outside. The boss lair is 160 blocks south (positive Z); glowing coral posts on the sea floor lead the way.

Terrain

The sea fills the world from its floor up to y 240; above that there are only 16 blocks of air under the sky. The sea floor rolls around y 140, with hills, reef crowns rising toward y 200 and rare trenches that drop below y 20. Caves run under the floor; some of them hold dry air pockets. Kelp forests, seagrass, coral reefs, sea pickles and spires of glowing Pressure Coral light the deep.

Block	Type	Drops
Abyssal Sand	Soft (shovel)	itself
Trench Rock	Stone (pickaxe)	itself
Pressure Coral	Light level 13	itself
Abyssal Salt Ore	Ore, everywhere from y -50 to y 200	Abyssal Salt
Nacre Vein	Ore, in the reefs and the upper floor (y 110 to 220)	Nacre
Abyssal Cobalt Ore	Ore, deeper down (y -20 to 110)	Abyssal Cobalt
Pearl Bed	Ore, in the deep rock and sand (y -50 to 60), rare	Pressure Pearl
Air Vent	On the sea floor, light level 6	itself

The rule: Oxygen

The mod keeps the vanilla air bar full and uses its own gauge instead: your breath, 0 to 100.

• Under water without air: -3 breath per second (about 33 seconds). At 0 you take 2 drowning damage per second.
• With a snorkel helmet: you breathe from its tank. It costs 1 second of tank per second, and it tops your breath back up (+6 per second, at 0.25 second of tank per point). Apnea Kelp halves the cost for 5 minutes, and the Survivor class reduces it.
• In air (an air pocket, a grotto, a habitat, the diving chamber, the surface): +10 breath per second, and the helmet's tank refills by 20 seconds per second.
• In a bubble column or over an Air Vent (up to 6 blocks above it): +5 breath per second and +12 seconds of tank per second, even under water.
• Oxygen Capsule: fills half of a worn helmet's tank, or gives +60 breath without a helmet.
• Abyssal Press: its Refill button fills a helmet to the brim (the one on your head, otherwise the emptiest one you carry), as long as the press stands deep under water.
• Blade Schools (-3 per second), Pressure Jellies (-2 per second) and the Leviathan's attacks (-5 or -15) take breath; the helmet pays them back from its tank.
• Pressure: under water below y 110 you take 1.5 damage per second. Each Diving piece lowers that limit by 22 blocks and the helmet's tier by 0 to 18 more: with the three Diving pieces and a Pearl Snorkel Helmet the limit is y 26.

The HUD shows the tank in the oxygen vial when you wear a snorkel helmet, with your breath as a thin line under it.

Snorkel helmets

One helmet for each ore of the world, all crafted at the Abyssal Press from 5 of their ore, 2 Glass Panes and 2 Kelp. They come out with a full tank. They are fragile: on top of the usual armor wear, every hit takes extra durability (half a point per point of damage for the Salt helmet), a hard hit spills some air, and every 30 seconds of use under water costs one more point. Mend them at the anvil with their own ore.

Helmet	Ore	Tank	Durability	Armor	Toughness	Extra wear per damage	Deeper
Salt Snorkel Helmet	Abyssal Salt	3 min	44	2	0	0.5	0
Nacre Snorkel Helmet	Nacre	5 min	66	3	1	0.35	6
Cobalt Snorkel Helmet	Abyssal Cobalt	8 min	110	3	2	0.25	12
Pearl Snorkel Helmet	Pressure Pearl	12 min	154	4	3	0.15	18

The tooltip shows the air left in the tank and the helmet's tier. The first common chests of the world sometimes hold a worn, half-full Salt Snorkel Helmet, and the Divers sell one for 8 Abyssal Salt.

Creatures

Every creature of the world lives under water: they swim in three dimensions, never drown and spawn in open, dark water (regular ones in groups of 1 to 3, swarms in groups of 2 to 4, elites alone and rarer), and from spawners in combat structures. See the Bestiary.

Creature	Health	Damage	Traits	Behavior (as coded)	Drops
Abyssal Hunter	157	20.9	aquatic	Swims straight at you.	Abyssal Salt (60%)
Blade School	73	11.9	aquatic	Fast swimmer. Drains 3 breath per second when within 3 blocks.	Abyssal Salt (60%)
Pressure Jelly	121	14.9	aquatic	Within 7 blocks: Slowness II, Mining Fatigue II and -2 breath per second.	Pressure Pearl (60%)
Bell Crab	242	17.9	aquatic, nesting	Plain melee attacker. Nesting: on death splits into 2 smaller copies (60% size, 40% health, 30% faster) that drop nothing.	Pressure Pearl (60%)
Trench Eel	182	23.9	elite, aquatic	Every 3.5 s at close range: Slowness VII (2.5 s) and Wither I (2 s).	Pressure Pearl (100%, 1-2)

Wildlife

Harmless creatures fill the sea. They never attack.

Creature	Health	Behavior	Drops
Lantern Shoal	6	A school of tiny glowing fish that darts away from swimmers.	Raw Cod
Glow Jelly	8	A small jellyfish that drifts slowly and lights the deep.	Glow Ink Sac

Items

Item	Kind	Rarity (souls)	Effect
Abyssal Salt	dust	rare (10)	Salt Snorkel Helmet and the Sapling of the Four Seasons (World 8).
Nacre	gem	rare (10)	Nacre Snorkel Helmet.
Abyssal Cobalt	ingot	rare (10)	Cobalt Snorkel Helmet and the Diving suit.
Pressure Pearl	gem	epic (30)	Pearl Snorkel Helmet and the Sapling of the Four Seasons (World 8).
Oxygen Capsule	consumable	common (1)	Right-click: fills half of a worn snorkel helmet's tank, or +60 breath.
Thruster	thruster	epic (30)	Right-click underwater: dash in the direction you look. 0.75 s cooldown.
Trench Trident	weapon	epic (30)	Sword-type weapon, about 23 attack damage. Gets a random class when crafted.
Salt, Nacre, Cobalt and Pearl Snorkel Helmets	snorkel	rare or epic	See Snorkel helmets.
Diving Chestplate	armor	epic (30)	9 armor, 2.5 toughness, +5 max health. Each piece lets you dive 22 blocks deeper.
Diving Leggings	armor	epic (30)	7 armor, 2.5 toughness, +4 max health. Each piece lets you dive 22 blocks deeper.
Diving Boots	armor	epic (30)	4 armor, 2.5 toughness, +2 max health. Each piece lets you dive 22 blocks deeper.
Apnea Kelp	food	common (1)	Oxygen lasts twice as long for 5 minutes, and +30 breath.
Tide Harpoon	weapon	epic (30)	21 damage in hand; thrown (23 damage, faster under water), it drags what it hits back to you. Abyssal Press. See New gear.

The Diving suit has no helmet any more: the snorkel helmet takes the head slot.

Station: Abyssal Press

Must be deep underwater: water directly above the press and 8 blocks above it. Its Refill button fills a snorkel helmet's tank to the brim (the one on your head, otherwise the emptiest one you carry). Crafted at the Matrix Workbench from 2 Piston (vanilla), 6 Unstable Alloy, 1 Inverted Crystal (World 6 boss defeated).

Output	Ingredients	Unlocked
Oxygen Capsule x3	4 Kelp (vanilla), 1 Abyssal Salt	Always
Thruster	2 Pressure Pearl, 4 Unstable Alloy	Always
Pressure Pearl	6 Abyssal Salt, 2 Prismarine Crystals (vanilla)	Always
Apnea Kelp x3	3 Dried Kelp (vanilla), 1 Abyssal Salt	Always
Salt Snorkel Helmet	5 Abyssal Salt, 2 Glass Pane, 2 Kelp (vanilla)	Always
Nacre Snorkel Helmet	5 Nacre, 2 Glass Pane, 2 Kelp (vanilla)	Always
Cobalt Snorkel Helmet	5 Abyssal Cobalt, 2 Glass Pane, 2 Kelp (vanilla)	Always
Pearl Snorkel Helmet	5 Pressure Pearl, 2 Glass Pane, 2 Kelp (vanilla)	Always
Trench Trident	8 Abyssal Salt, 1 Stick (vanilla)	Always
Diving Chestplate	8 Abyssal Cobalt	Always
Diving Leggings	7 Abyssal Cobalt	Always
Diving Boots	4 Abyssal Cobalt	Always
Tide Harpoon	4 Abyssal Cobalt, 2 Nacre, 4 String (vanilla)	Always

Every weapon, tool and armor piece crafted here gets a random class (see Equipment classes).

Boss: Pressure Leviathan

3027 health, 35.8 damage, phases at 66% and 33% of its health. It sleeps in a sunken trench temple: the temple is cut 10 blocks below the level of the diving chamber, at the bottom of a trench open to the sea, and two beacon pillars rise from its forecourt to the surface. Its heart wakes it when you swim within 10 blocks. It swims freely, never drowns and does not float up. When it falls the alcove behind the seal opens on three chests (the world's rarest materials, a piece of its gear or a snorkel helmet, and riches). It drops the Leviathan Core; every player within 64 blocks gets 100 souls, 2 Shell Shards and credit for the kill.

Attack	What the code does
Light: Tail Lash	Frontal strike: 60% damage within 3.2 blocks.
Medium: Charge	Charge (90% damage on impact) and -5 breath to every player within 20 blocks.
Signature: Abyssal Pull	Abyssal pull toward it from 18 blocks and -15 breath to every player within 20 blocks.
Final phase: Depth and oxygen worsen	Phase change only.

Its hits are hard on a snorkel helmet: a Salt helmet does not survive two of them. Bring a better tier, a spare, or capsules.

Full mechanics, timings and multiplayer scaling: Bosses. Its animations, attack by attack: Boss attacks.

Structures

Eleven structure types generate in this world, all on the sea floor (the eleventh, the Drowned Bastion, since 0.4.0). Several of them hold dry refuges where your breath and your helmet refill: the Air Grotto (a glass dome with beds, entered through a flooded tunnel), the Diving Bell and the habitats of the Pressure Station.

Structure	Role	Size	Rarity	Layout	Frequency	Contents
Hunters' Trench	combat	large	common	chasm	about one per 26 x 26 chunks	a mob spawner and a loot chest
Dead Reef	combat	medium	common	ruin	about one per 18 x 18 chunks	a mob spawner and a loot chest
Sunken City	combat	large	rare	city	about one per 42 x 42 chunks	a mob spawner and a loot chest
Wreck	exploration	medium	common	wreck	about one per 18 x 18 chunks	two loot chests
Diving Bell	exploration	small	common	bell	about one per 18 x 18 chunks	an air pocket and two loot chests
Air Grotto	exploration	medium	common	cocoon	about one per 18 x 18 chunks	a dry refuge and two loot chests
Abyssal Temple	story	large	unique	temple	about one per 72 x 72 chunks	a chest with a Journal Page, and a painted frieze
Sunken Lighthouse	story	medium	unique	lighthouse	about one per 64 x 64 chunks	a chest with a Journal Page, and a painted frieze
Pressure Station	utility	large	rare	lab	about one per 42 x 42 chunks	dry habitats, an Abyssal Press and a Diver
Vault of the Deep	secret	small	unique	vault	about one per 64 x 64 chunks	a chest with a Journal Page and the world's Hidden Doll
Drowned Bastion	combat	large	rare	bastion	about one per 42 x 42 chunks	mob spawners and a vault chest

World events

While you are here, now and then (see World events):

• Invasion: three waves of the world's creatures, the last led by a glowing warlord, one of its elites; beat it within four minutes for a reward chest and 70 souls each.
• Surge: Crushing Current. For two minutes the world's rule bites twice as hard. On top of it: A deep current drags you while you swim. Weather it for 15 souls.
• Travelling merchant: Drifting Diver, for five minutes: Tide Harpoon for 6 Abyssal Cobalt, Shell Shard for 2 Pressure Pearl, Nacre Snorkel Helmet for 6 Nacre (each trade twice).

People: Diver

Station chiefs and mechanics who keep the pressure station running. They live under water and walk the sea floor. Prices drop by 10% at karma +25 and rise by 10% at karma -25; at karma -50 or lower they refuse to trade one time in three (see Souls and karma).

They want	They give
Abyssal Salt x3	Oxygen Capsule x3
Pressure Pearl x1	Apnea Kelp x4
Abyssal Salt x8	Salt Snorkel Helmet x1

Quests

Quest	Type	Description	Objective as coded	Reward
Under Pressure	Guide	Craft a Salt Snorkel Helmet at the Abyssal Press.	Craft Salt Snorkel Helmet	8 Oxygen Capsule
Compress	Guide	Press something at the Abyssal Press.	Craft Pressure Pearl	40 souls
The Silent Station	People	Repair 3 station cables.	Carry 6 Abyssal Salt	1 Thruster
The Wreck's Crew	People	Recover 3 crew plates.	Kill 10 Blade School	40 souls
The Signal	Karma	Rescue the castaways (+10) or divert their oxygen (-10).	Choose Help or Betray in the Journal	60 souls
One Breath	Challenge	Defeat a Trench Eel.	Kill 1 Trench Eel	Title: Cold Blood

Achievements

Achievement	Type	Description	How it unlocks in the code	Reward
Great Depth	progress	Open World 7.	Enter World 7.	5 souls
Pressurized	progress	Breathe through a snorkel helmet.	Breathe from a helmet's tank under water.	5 souls
Silence of the Trenches	progress	Defeat the Leviathan.	Land the killing blow on Pressure Leviathan.	5 souls
Extreme Dive	explore	Reach the deepest trench.	Swim below y 30 in World 7.	10 souls
Open Sea	explore	Visit the 10 structure types.	Step inside all 10 structure types of this world.	10 souls
Wet Paper	explore	Find the 5 Journal pages.	Collect the 5 Journal Pages of this world.	10 souls
School Scattered	combat	Kill 5 Blade Schools.	Land the killing blow on Blade School.	-
Last Breath	combat	Beat the Leviathan with under 5% oxygen left in your helmet or your lungs.	When the Leviathan dies: the helmet's tank (or your breath without air in a helmet) is under 5%.	-
Forgotten Plate	hidden	Search a sunken wreck.	Step inside a Wreck.	-
Drowned Doll	hidden	Find the hidden doll of the world.	Have Hidden Doll 7 in your inventory.	-

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