Deep Dark

Generates between Frozen Caves and Mushroom Gorge, has the same generation as Deeprock Caverns, a spaghetti-like pattern. It is one of the rarest biomes, slightly less rare than Mushroom Gorge.

A screenshot from the Infinity Cave mod, showing the deep dark biome.

Structures

Deep Dark only has one structure, the Deep Temple, which is one of the best structures loot-wise in the game. Having a high possibility of high tier enchantlets, and tons of enchanted books guaranteed to be protection 3.