The Hallow



The Hallow is a Hardmode surface biome. It is characterized by pastel-colored fairytale graphics, with cyan-colored grass, multicolored trees, and a large rainbow in the background, as well as similarly whimsical-looking (though dangerous) enemies. The Underground Hallow biome can be found directly beneath a naturally-generated Hallow biome.

The Hallow does not exist in newly-generated worlds. It is generated along with a large Underground Hallow biome when the Wall of Flesh is defeated for the first time and the world converts to Hardmode. This initial conversion can replace preexisting sections of the world's "evil biome" (Corruption or Crimson). If areas of Jungle or Mushroom Biome are included in the conversion area, stone will be converted but the (mud based) grasses will be unaffected.

Once generated, Hallow spreads in a manner similar to the evil biomes; Pearlstone, Pearlsand, and dirt blocks growing Hallowed grass will spread Hallow to neighboring blocks, causing Hallow enemies to spawn over ever-larger areas. Hallow can also be seeded in new areas via Hallowed Seeds, Holy Water, or Blue Solution. See below or the Biome spread page for more details.

The Hallow is the only environment through which the Corruption and Crimson cannot spread at all, In turn, the Hallow mostly cannot spread through the evil biomes (it can convert Crimson grass), and unlike them, it cannot spread through mud areas such as found in Jungles or Mushroom Biomes.

The Dryad can tell the player the percentage of Hallow and Corruption/Crimson in the world.

Spread
The Hallow spreads itself, similar to the evil biomes. This means that it slowly converts certain susceptible tiles that are in the vicinity of existing Hallowed blocks. Defeating Plantera for the first time reduces the speed of the Hallow's spread by 1/2 (50%). Hallow can convert Crimson (but not Corruption) grass blocks, but otherwise cannot convert blocks already claimed by an evil biome. This can result in areas where the Hallow and an evil biome intertwine closely. If Hallow is introduced into a pre-Hardmode world, its spread will be very limited, similarly to the evil biomes.

Trivia

 * The verb "to hallow" means "to make holy", indicating that the name Hallow likely means "holy land".

Hallowed Desert


When the Hallow spreads through desert, it becomes Hallowed Desert. It is very similar to the Hallow: the music theme is the same, the enemies are the same (except for the Light Mummy and Crystal Thresher), and the background is slightly different.

The sand is replaced by pearlsand. Although their color is different, cacti still drop cactus when cut, and waterleaf plants are also able to grow.

History
Das Heiligtum Le Sacré 神圣之地