Abyss



"The ocean depths are trembling..."

The Abyss is an aquatic biome added by the Calamity Mod which spawns upon world creation. It is located under the Sulphurous Sea on the Dungeon side of the world through a chasm on the seafloor. It is extremely deep, dark, and perilous, filled with deadly enemies, which increase in strength as the biome grows deeper. Because many enemies in the Abyss are initially passive, only becoming hostile when hit or when in close proximity to the player, stealthiness should be greatly prioritized while exploring the biome.

The Abyss is divided into four distinct layers, each with a different set of enemies that will spawn.
 * Layer 1 is the entrance to the Abyss and is empty and open. No real danger is present in this layer.
 * Layer 2 is the first exploration site of the Abyss. There will be 'islands' in the middle and on the sides of the Abyss, which have small houses on them. These houses have locked Shadow Chests containing either powerful late Pre-Hardmode weapons or useful items for further Abyss exploration. As a Shadow Key is required to obtain the loot from the chests, it is highly recommended to explore these layers after Skeletron has been defeated.
 * Layers 3 and 4 contain the most dangerous enemies present in the biome, which include the biome's mini-bosses. Layer 3 is similar in structure to layer 2, while layer 4 is relatively open until it comes to a closing point. A Shadow Chest containing the Terminus can be found at the bottom of the Abyss. It is recommended to explore these layers after Polterghast has been defeated.

The upper two layers of the Abyss are mostly composed of Abyss Gravel, with Abyss Gravel Walls as a background. The third layer begins replacing Abyss Gravel with Voidstone and Voidstone Walls, while the fourth layer is completely made out of Voidstone. Planty Mush, Tenebris and Scoria Ore can also be found in the 2nd and 3rd layers. Several Pots are scattered around the islands, containing several useful drops.

Light Level
Without a sufficient level of light, the player's vision may be reduced (similarly to the Darkness debuff) or blackened completely (similarly to the Obstructed debuff), depending on how deep they've descended into the Abyss.
 * In Layer 1, the player's vision will be reduced unless they have a light level of 1 or higher.
 * In Layer 2, the player's vision will be blackened unless they have a light level of 1 or higher, and reduced unless they have a light level of 3 or higher.
 * In Layer 3, the player's vision will be blackened unless they have a light level of 3 or higher, and reduced unless they have a light level of 5 or higher.
 * In Layer 4, the player's vision will be blackened unless they have a light level of 5 or higher, and reduced unless they have a light level of 7 or higher.

In Death Mode, Abyss light level requirements are increased by 25.

The following items increase the player's light level. These values are cumulative, and stacking several of them at the same time is required for maximum vision in the Abyss. In Death Mode the effectiveness of light level increasing accessories and buffs is decreased by 25%.
 * Buffs and Accessories that increase light level by +1 / :
 * Crimson Heart, Shadow Orb, Magic Lantern, or Radiator light pets
 * Aquatic Emblem
 * Arctic Diving Gear, Abyssal Diving Gear, or Abyssal Diving Suit
 * The Camper
 * Giant Pearl
 * Jellyfish Necklace, Jellyfish Diving Gear, Deific Amulet, or Rampart of Deities
 * Mining Helmet
 * Radiant Ooze during Nighttime or Ambrosial Ampoule
 * Aquatic Heart
 * Buffs and Accessories that increase light level by +2 / 1:
 * Blazing Core
 * Baby Ghost Bell, Fairy, or Flickerwick light pets
 * Shine buff
 * Lumenous Amulet
 * Buffs and Accessories that increase light level by +3 / 2:
 * Wisp, Suspicious Looking Eye, or Ocean Spirit light pets

Breath
The breath meter drains faster in the Abyss, with each deeper layer applying more severe breath loss. Players with zero breath in the Abyss will lose health far more rapidly than if they were drowning in normal water. Finally, the Crush Depth debuff is commonly inflicted by enemies in the Abyss and causes the player's breath to drain even quicker. These conditions make underwater breathing equipment a necessity for players wishing to explore the Abyss.

The first layer of the Abyss reduces the player's breath by 2 every tenth of a second, resulting in a net loss of 20 breath per second. Each layer beyond the first reduces the player's breath three times as quickly as the previous: the second layer takes away 60 breath per second, the third layer takes away 180, and the fourth takes away 540.

The Abyss ignores all items that normally grant permanent underwater breathing, such as the Gills Potion, Neptune's Shell, and the Ocean Crest. These items are still useful as they separately help reduce the breath loss the Abyss applies to the player.

Breath loss rate
The following items reduce how frequently the Abyss takes breath away from the player. These effects add together to create an overall delay multiplier that slows down the Abyss' breath loss:
 * Gills buff or Ocean Crest: +4
 * Any item which lets the player ignore water physics, as listed below: +5

The delay multiplier is capped at 50. The Abyss takes away breath  times more slowly from the player.
 * A full set of Victide armor: +10 (ignores water physics and adds +5 on its own)
 * Diving Helmet, Diving Gear, or Jellyfish Diving Gear: +10
 * Aquatic Emblem: +14 (inherits Gills and adds +10 on its own)
 * Neptune's Shell, Moon Shell, or Celestial Shell: +15
 * Aquatic Heart after Skeletron has been defeated: +20 (ignores water physics and adds +15 on its own)
 * Arctic Diving Gear or Abyssal Diving Gear: +20 (inherits Diving Helmet and adds +10 on its own)
 * Abyssal Diving Suit: +39 (inherits Abyssal Diving Gear and Gills and adds +15 on its own)

Breath loss amount
The following items reduce the quantity of breath taken away by the Abyss. These effects do not multiply together. Rather, they add onto each other and create an overall percentage to reduce the Abyss' breath loss by: This percentage reduction is capped at 95%. At this cap, the Abyss removes 20 times less breath from the player.
 * Gills buff, Ocean Crest, or Fin Wings: -20%
 * A full set of Victide armor: -20%
 * Diving Helmet, Diving Gear, or Jellyfish Diving Gear: -25%
 * Aquatic Emblem: -45% (inherits Gills and adds -25% on its own)
 * Neptune's Shell, Moon Shell, or Celestial Shell: -15%
 * Aquatic Heart after Skeletron has been defeated: -30%
 * Arctic Diving Gear or Abyssal Diving Gear: -50% (inherits Diving Helmet and adds -25% on its own)
 * Abyssal Diving Suit: -100% (inherits Abyssal Diving Gear and Gills and adds -30% on its own)

Drowning damage
A player drowning in the Abyss takes extra damage in addition to the vanilla game's health drain from drowning. More precisely, the Abyss reduces the player's health instead of their breath if their breath meter is empty. With no relevant equipment, drowning in the Abyss deals an extra 30 damage per second in Layer 1, 60 damage per second in Layer 2, 120 damage per second in Layer 3, and 240 damage per second in Layer 4. This damage is reduced by 30 per second if the Depths Charm or Abyssal Diving Gear is equipped; this damage is further reduced by 60 damage per second if the Abyssal Diving Suit is equipped. The extra drowning damage dealt by the Abyss is slowed down by all items which reduce the rate of breath loss.

Enemy Detection
Abyss enemies have their own player detection system independent from enemy aggro, with a default detection radius and a reduced detection radius. Once an enemy has detected the player, it will not stop chasing them until it gets killed, moves too far from the player, or the player dies. Using either Anechoic Coating or Anechoic Plating will reduce enemy detection radii, these effects do not stack. Most enemies will detect the player regardless of distance if they are damaged.

Additionally, enemy detection radii will be:
 * Multiplied by 3 if the player has the Fish Alert debuff.
 * Multiplied by 0.65 if the player is wearing the Abyssal Mirror.
 * Multiplied by 0.3 if the player is wearing the Eclipse Mirror.

Defense
Being in the Abyss decreases the player's defense, with more severe reductions occurring at the deeper levels. All of these defense reductions can be reduced to one-third effectiveness by equipping the Anechoic Plating or Abyssal Diving Suit:
 * Layer 1: -15 defense (-5 if wearing appropriate accessory)
 * Layer 2: -30 defense (-10 if wearing appropriate accessory)
 * Layer 3: -60 defense (-20 if wearing appropriate accessory)
 * Layer 4: -120 defense (-40 if wearing appropriate accessory)

Unlike many defense reducing effects, the Abyss can reduce the player's defense below zero, causing them to take increased damage.

Fishing
When fishing in the Sulphurous Sea the player can catch Abyss related items, these depend on the player's fishing power, and are as follows:
 * Abyssal Crate - Can be caught with any fishing power.
 * Planty Mush - Can only be caught with 0 to 80 fishing power.
 * Planty Mush's coded requirement is actually 40 to 80. However, as this item replaces Junk catches in the Abyss, it is technically 0 to 80.
 * Alluring Bait - Can only be caught with 40 to 159 fishing power.
 * Abyssal Amulet - Can only be caught with 110 to 239 fishing power.

Tips

 * While the player can explore the entire biome even while in Pre-Hardmode, they are very unlikely to survive due to the intense pressure and strong enemies present in the deeper parts of the Abyss.
 * Having the Stat Meter is extremely helpful as it shows breath, defense loss and current light level.
 * The Aquatic Heart and the Shrimpy Truffle can prove very useful due to their increased mobility in water. The Cute Fishron mount is always wet and increases damage whereas the Aquatic Heart grants the Ocean's Blessing buff. Both additionally slow the rate of breath loss.
 * Do not use the Rod of Discord or Normality Relocator in the Abyss at any time. If the player is affected with Chaos State while in the Abyss, a nigh-invincible and hostile Adult Eidolon Wyrm will spawn regardless of their progression in the game.
 * Using torches that can be placed underwater, such as the Cursed Torch, Ichor Torch or Abyss Torch can help with the darkness of the abyss.
 * To restock on air while exploring the Abyss, the player can use a Portal Gun to quickly teleport between the surface and their current position. Set up a portal somewhere the player can breathe beforehand, and whenever they need air, place the second color portal.
 * The player could dig to the left/right of the Abyss to regenerate breath in a Underground biome to avoid the rapid health loss that occurs when air bubbles are used in the Abyss.

Trivia

 * The theme that is heard while in the 1st and 2nd layers of the Abyss is Hadopelagic Pressure, which was composed by the artist DM DOKURO.
 * If the Calamity Music add-on mod is disabled, The Underworld's theme will play through all layers of the Abyss instead.
 * The theme that is heard while in the 3rd layer of the Abyss is R'LYEH, which was made by wiki editor RoverdriveX.
 * It was intended to be just a placeholder but was kept due to positive reception from the community.
 * The name is a reference to the sunken city of R'lyeh, in H.P. Lovecraft’s “The Call of Cthulhu”, which fits well with the Cthulhu themed bosses.
 * The theme that is heard while in the 4th layer of the Abyss is void, which was also composed by the artist DM DOKURO.
 * Some of the creatures in the Abyss are based on the game Subnautica, though most are based on real-life ocean creatures.
 * If the player drowns in the Abyss, the death message will either appear as " is food for the Wyrms." or "Oxygen failed to reach  from the depths of the Abyss."
 * The Abyss generates under the Dungeon-side Ocean in order to prevent conflict with the Thorium Mod's Aquatic Depths biome, which always generates under the Jungle-side Ocean.
 * The Abyss and the Sulphurous Sea are comparable to the Pelagic zone, the way the ocean's layers are categorized, with the Sulphurous Sea being the Epipelagic Zone, the first layer of the abyss being the Mesopelagic Zone, the second layer being the Bathypelagic Zone, the third layer being the Abyssopelagic Zone, and the fourth and final one being the Hadopelagic Zone.
 * Hadopelagic Pressure does not play in the 4th layer even though it is considered the Hadopelagic Zone.