Underground Hallow

The Underground Hallow is a dangerous Hardmode biome, being one of the biomes that spawns when the Wall of Flesh is defeated. It is the underground version of the surface-level Hallow, and appears in the Cavern layer. It operates similarly to the surface Hallow, being comprised of Pearlstone and Pearlsand; though it spawns different enemies, along with Crystal Shards, a common Hardmode crafting material. The Underground Hallow spreads just like its surface counterpart, The Hallow, and similarly will conflict with Corruption and Crimson, as well as their underground variants.

Underground Hallow does not suppress the spawn of other underground and cavern enemies.

All enemies killed in the Underground Hallow have a 1/5 (20%) chance to drop a Soul of Light. In Expert mode this chance increases to a 1/3(33%) chance.

Additionally, small pockets of Underground Hallow can be created through the breaking of Demon/Crimson Altars, which has a 33% chance to convert a single random Stone Block in the world into Pearlstone.

Note: Most characteristics of the surface Hallow apply to the Underground Hallow, with the exception of the enemies that spawn. See The Hallow for more extensive information.