Atmospheric Nether expands on the vanilla Nether by altering major worldgen aspects while aiming to encourage adventure and exploration in a geographically and geologically immersive Nether!

What To Expect

Terrain

• Continental regions hosting valley-like terrain and plateaus, as well as rare small peaks. These regions are surrounded by towering and dramatic cliffs that stand in as walls attempting to hinder your advancement. Often at the center of these continents are what remain of ancient volcanic activity, sometimes leaving extremely vast lava oceans.

• Subterranean lava rivers carved into the mountain ranges of the continents by the lava rivers flowing across the landscape. They twist and turn within the mountains, and sometimes cut through!

• Caves reminiscent of those found in the Overworld. Open, expansive caves and tunels meet claustrophobic crevices to form unique networks. These cave systems are generally not open via the surface, but with some exploring you can still find large entrances.

• "Entrance caves", which you may recognize from the surface of the Overworld, are randomly sealed at the surface within continental regions.

• World height of the Nether extends from -64 to 384, where y256 is the top of the bedrock roof.

Biomes

There are 27 new biomes, of which you can read about their details and features in the spoliers below. Check the gallery for images of some of these biomes!

• 7 new forest biomes

Forests

Old Growth Crimson and Warped Forests

These forests are characterized by dense vegetation and different fungal types that form in such environments, as well as by strings of shroomlights shining from above. Their respective mobs may spawn more frequently here.

Wailing and Old Growth Wailing Forests

These forests were once normal crimson forests. They are like their crimson counterparts, though they also are characterized by soul sand and soul soil permeating through the ground and ceilings. Many crimson fungi lost their lights, and a frequent shrieking can be heard. These biomes tend to be "emptier," for other entities somewhat avoid them. Otherwise, the scent of decay from zombified piglins and zoglins permeate the air (Zoglins have a 35% chance of spawning as a baby in pre-1.21.2, and 20% chance of spawning as a baby in 1.21.2+).

Dispirited and Old Growth Dispirited Forests

The fungi of these forests have also lost their light, and have succumbed to the soul sand and soil. While they are physically like their wailing counterparts, these forests are also clouded by an air of depression and anger. The enderman here do not take kindly to others. These forests scream out, to no avail.

Ancient Forests

Long lost forests of the nether were preserved by volcanic activity ages ago. While you can no longer find living instances of these forests, you can find their snapshots-in-time within the continental regions. Some magma cubes have made a home here, eating brown mushrooms sprouting from the ground.

• 9 new cave biomes

Caves

Blackstone Caves

Blackstone caves formed from ancient magma chambers. They're made almost entirely of blackstone, only interrupted by large strands of glowstone, as well as the occasional glowstone stalagmite and stalactite.

Quartz Crystal Caverns

These caves host plenty of nether quartz ore, and are home to large quartz crystals! They are only found within and near the continents, and frequently form around the lava rivers.

Gilded Caves

These caves host plenty of nether gold ore. Also found only within and near the continents, especially around the lava rivers, they often mix with quartz crystal caverns to form a treasure hunter's paradise.

Mantle

Thick slabs of magma are layered throughout these biomes with large amounts of basalt sprinkled with blackstone, and both magma blocks and lava coat the surfaces of these caves. Magma cubes love these ones. You can also find giant columns of magma blocks here!

Mournful Hollows

Mournful Hollows are almost entirely made of soul sand with trails of soul soil. Good luck getting through them with so many skeletons!

Crimson and Warped Caverns

These caverns host distant branches of their respective forests. They host the same mobs, but different fungi that adapted to the shallow lava lakes. They are often coated with bands of nether wart blocks, with the roofs hosting shroomlights.

Nether Substratum

Only found underneath the mountains surrounding the continents, these caves were colonized by red and brown mushrooms. The ground here has degraded into large seams of gravel, with many columns of gravel still intact. Perfect for emergency mushroom soup!

Stifled Depths

In the deepest parts of the Nether, most life struggles to exist. No mobs call these caves their home.

• 5 subterranean river biomes

Rivers

Carved Rivers

The ordinary carved river. It can take on the material of surrounding biomes, though most often it is surrounded by netherrack.

Stony Carved Rivers

Basaltic tunnels with blackstone stripes characterize this type of carved river.

Crimson and Warped Carved Rivers

These rivers have been colonized by the two fungi, and tend to be alight with shroomlights.

River Styx

You'll find naught but condemned souls in these rivers.

• 6 continental biomes

Continental Biomes

Continental Barriers and Basaltic Abrasions

These biomes exist at the boundaries of continents, and occasionally exist as lone mountain ranges. They are functionally the same, though basaltic abrasions are made almost entirely of basalt, with slabs of blackstone layered throughout.

Soul Sand Floodplains

Floodplains deeply infused with sheer numbers of souls. Broken soul soil trails wind across the floodplains, and rivers of lava flow across. Functionally the same as soul sand valleys. Good luck crossing these...

Volcanic Remnants

Remnant volcanoes full of magma, basalt, blackstone, and gravel. These volcanic remnants exist deep within the continents and form more mountain ranges.

Continental Deltas

Lava deltas leftover from volcanic activity. They feature terraces of still lava and exist close to volcanic remnants.

Volcanic Sea

The vast volcanic seas are leftover from ancient eruptions. It can be difficult to imagine that the volcanic remnants stretch all the way around them. Hopefully you find some peace in such an extreme environent. Why not build an outpost or two? It's so secluded!

Ancient Debris

• Vanilla ancient debris y-level range is unchanged.

Spoiler! There is a biome where ancient debris spawns more frequently and in larger veins. Good luck finding which biome and at what y-levels!

Technical

• This mod adds a data-driven speleothem feature (if you are familiar with Lithostitched, you may know of such a thing already). It is practically the same as the large dripstone feature, except with a customizable block and replaceable tag. It uses the same configured feature file as the large dripstone feature, except it also includes fields "block" and "base_tag" for the custom block and tag. You can find examples of this in the source code directory "src/main/resources/data/tbm_nether/worldgen/configured_feature/cave/speleothem/". You can utilize this feature via datapack to add your own speleothems to whatever biome you wish!

• This mod also changes the zoglin's spawn rules to be exactly the same as hoglin's, meaning they can spawn regardless of light as long as the valid block below them is not a nether wart block. As a result of this, you can add zoglins to the JSON file of any biome you'd like as well.

• Because of the extended world height range, mob farms will be less efficient than their vanilla counterparts.

• It is recommended to pregenerate the Nether when using this mod (and most other worldgen projects), because worldgen can be very laggy.