
The first layer of the Abyss is mostly composed of Sulphurous Shale, with Hardened Sulphurous Sandstone Walls as a background. It is recommended to explore this layer after Polterghast has been defeated. An Abyss Shell Fossil is also found at the very bottom of the Void. A Void Chest containing the Terminus can be found at the bottom of the Abyss. Layer 4 is made of Voidstone and Voidstone Walls and is relatively open, with chunks of floor coming out of the walls, until it comes to a closing point.

The Abyss is divided into four distinct layers, each with a different set of tiles that generate and enemies that spawn. 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.

It is extremely deep, dark, and perilous, filled with deadly enemies, which increase in strength as the biome grows deeper. It is located under the Sulphurous Sea on the Dungeon side of the world through a chasm on the seafloor. The Abyss is an aquatic biome added by the Calamity Mod which spawns upon world creation. "While there are many sightless crevasses in the deep sea, this one is a unique geological marvel." If you were looking for something other than the Abyss biome, see Abyss (disambiguation). The Abyss biome, as viewed on the map in a large world.
