Undermod

Discover the mysteries of interconnected underground biomes. From underground forests to vast ancient sewers that extend between villages, surprise might be waiting right beneath your feet ⏚

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Undermod connects its underbiomes with one another in a meaningful way, creating new integrated exploration adventures in the underground. Explore dangerous places and find novel blocks to bring home for your builds!

Available for Minecraft 1.16 and 1.20.1. Forge for now.

MC 1.12 and server-only versions are also on the horizon. Compatible with most world generation mods.

Created by Mystronics. *Most textures and models by GGVegan.

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What does Undermod include?

• Adds natural and artificial underground biomes that depend on surface biomes.
• Adapts to existings worlds so you don't miss anything, preventing hard seems between old and new chunks.
• Connects faraway underbiomes with each other. For example, sewers usually discharge their water into underground rivers or seas.
• Completely procedural. No fixed designs! Undermod generation rewards exploration and keeps the door open for low-probability extreme cases (for example, megacaves). There is always the possibility of surprise.
• Works along with other world generation mods and follows the spirit of vanilla Minecraft.
• Powered by new Mystronics world generation engine, optimized for low lag.

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Underbiomes

If Undermod gets enough downloads, you will see more of these coming!

Ancient Sewers

Sewers can be found under Minecraft villages, sometimes linking multiple villages together through a net of flooded underground tunnels that stretch beneath the land. Water falls through narrow channels into larger ones, eventually discharging into underground rivers, or occasionally subterranean seas. The air is thick and water tainted, be prepared for poison.

Wandering these passages, one might encounter long forgotten chambers - some abandoned, other repurposed. Outcasts have made these places their home - expect old living quarters, bandit hideouts, and more. Some say that villagers built on top of sewers for their hidden wealth and secret paths, while others believe that their ancestors took part in their construction.

Wildlife has also settled inside sewers. Mushrooms, spiders, rats and slimes are well adapted to this biome. And in the dark waters, something moves...

Tips to find them

Look for subtle entrances in villages. However, you will need to visit several villages to find sewers. Occasionally, they might be visible when they cross chasms or rivers. An easier way to visit sewers is by buying exploration maps from cartographer villagers. If you are out of emeralds or far from villages, it's also possible to find sewer maps hidden by bandits in underground forests.

Underground Forests

Surface forests can extend downwards in Undermod. Trees and other plants prosper under sinkholes, that let sunlight through into underground caverns. Certain type of small tree can even thrive under very dim light conditions, populating deeper caves that are completely dark to the human eye.

This biome is very rich in coal, and can feature small amounts of lapis lazuli or even diamonds and glowstone. Given their size, underground forests usually give way to natural caves and chasms, and in rare cases explorers may also find connections to mineshafts, underground rivers or even ancient sewers, making these forests not just places of life, but crossroads in the depths.

Tips to find them

Underground forests are fairly common, so you should be able to find them by exploring surface forests. Search for pits or sinkholes that show you what lies below. However, not all surface forests have an underground counterpart.

Craters

Formed by the impact of fallen asteroids, craters were carved into to the Overworld by massive explosions. These depressions cut through the earth below sea level, exposing caves, chasms and new mineshafts to the sun. Remains of large meteorites can normally be found at their center, with diverse mineral composition.

Over time, nature has reclaimed these craters. Depending on their location, they may be covered in grass and trees, filled with water, or left as barren wastelands. Explorers are always on the lookout for meteorites because they say they can make you a fortune. However, be it out of superstition or due to some deeper knowledge, villagers avoid settlements anywhere near these eerie places; unworldly scars of the earth...

Tips to find them

Craters are obviously easy to spot at surface level, but they are few and far between. If you want to find one without extensive exploration, your best bet is to look for old maps lost within ancient sewers, that mark areas of known celestial impact sites.

Underground Rivers

Water makes its way below surface in Undermod, creating long rivers that can extend under the Overworld. Explorers find underground rivers specially useful, because they provide a mostly safe passage to move by boat between distant surface points across a region.

They feature less minerals than normal caves, but can connect several cave systems together. Some rivers eventually flow into subterranean seas.

Tips to find them