The Undergarden is a Minecraft mod that adds a whole new dimension below the Overworld, a dark underground world of glowing fungus, strange forests, poisonous bogs and the ruins of a civilization that’s long gone. You get there through a portal made of Stone Bricks, which you light with a Catalyst instead of Flint and Steel.
Once you’re down there, you start again with a new set of ores and gear, from Cloggrum and Froststeel up to Utherium and the Forgotten tools you get from the Catacombs. This guide covers how to get into the Undergarden, what to mine first, which mobs are worth knowing about, and how to take on the Forgotten Guardian for the best gear in the mod.
How to Get to the Undergarden
Getting to the Undergarden takes a Catalyst and a portal frame, and it works a lot like building a Nether Portal. The Catalyst is the item you use to light the frame, and it isn’t used up, so one Catalyst will open every portal you build for the rest of your world.
Craft a Catalyst
Gold, Iron and a Diamond
The 
Catalyst is made from four 
Gold Ingots, four 
Iron Ingots and a single 
Diamond in the middle of a Crafting Table. That’s the only real cost of getting into the dimension, as the frame itself is made from blocks you’ll usually have plenty of by the time you want to go.
Hang on to the Catalyst once you’ve made it, as you’ll need it again if you ever want to build a second portal, or if you need to relight one on the Undergarden side. It works in the Overworld and in the Undergarden, but it won’t light a frame in the Nether or the End.
Build the portal frame
Stone Bricks or Deepslate Bricks
Build a frame the same shape as a Nether Portal, with an opening at least one block wide and two blocks tall inside it. 
Stone Bricks are the usual choice, but Mossy Stone Bricks, 
Deepslate Bricks, Deepslate Tiles, Polished Deepslate and the Undergarden’s own Depthrock and Shiverstone Bricks all work as well.
Light it with the Catalyst
Right-click the frame
Right-click the inside of the frame with the Catalyst and the portal will fill in and open, the same way Flint and Steel lights a Nether Portal. Step inside and you’ll be taken down to the Undergarden, with a matching portal built for you on the other side so you can get back.
Why Your Undergarden Portal Isn’t Working
Most of the time it’s the frame. Cracked Stone Bricks and Chiseled Stone Bricks don’t count, and neither does plain Stone or Cobblestone, so check every block in the frame is one of the ones listed above. The frame also has to be a complete rectangle, and you need to click the empty space inside it rather than the frame itself.
The other common problem is where you’re building it. The Catalyst only works in the Overworld and in the Undergarden, so a frame built in the Nether or the End will never light. If the frame is right and you’re in the Overworld, break a block and rebuild it to make sure nothing is out of place, as one wrong block stops the whole frame.
Getting Started in the Undergarden
The Undergarden is dark, and a lot of the mobs you’ll meet first are hostile, so you’ll want to go through prepared rather than finding out the hard way. Bring a stack of Torches, some food and a decent sword, as your Overworld gear works just as well down here while you get set up.
Mine Cloggrum right away
Your first new ore
Cloggrum Ore is everywhere in the Undergarden, so it’s the first thing you’ll find and the first thing worth mining. Smelt the 
Raw Cloggrum into 
Cloggrum Ingots, which make tools and armor on the same level as Iron, and you’ll have a full set of new gear before you’ve gone very far from the portal.
Make a Slingshot
A ranged weapon that uses stones
A 
Twistytwig and five 
Sticks make a 
Slingshot, and it fires the Depthrock Pebbles that you’ll pick up while mining. Twistytwigs drop from breaking Wigglewood Leaves, only rarely though, so break plenty of leaves in the Wigglewood Forest until you get one.
It’s a lot cheaper to keep running than a Bow, since the Undergarden is full of Depthrock and every Mog and Stoneborn drops more Pebbles. The Slingshot section further down covers the other ammo and the three enchantments it can take.
Kill Rotspawn for Utheric Shards
The start of Utherium
The Rotlings, Rotwalkers and Rotbeasts you’ll run into are called Rotspawn, and when you kill them they drop 
Utheric Shards. Nine Shards craft into one 
Utherium Crystal, which is the mod’s diamond level material, so every Rotspawn you kill gets you a bit closer to Utherium gear.
Ores and Gear Tiers
The Undergarden has four tiers of tools of its own, and each one has a little extra on top of its stats. Cloggrum and Froststeel sit at Iron level, Utherium is on par with Diamond, and the Forgotten tools at the top mine like Netherite.
| Tier | Where It Comes From | Mining Level | Durability | Extra Effect |
|---|---|---|---|---|
| Cloggrum | Cloggrum Ore, everywhere | Iron | 286 | None |
| Froststeel | Froststeel Ore, frozen biomes only | Iron | 575 | Slows whatever you hit |
| Utherium | Utherium Ore and Utheric Shards | Diamond | 1,279 | +50% damage to Rotspawn |
| Forgotten | Smithing Template from the Catacombs | Netherite | 1,876 | +50% damage to Undergarden mobs |
The durability column is where Froststeel earns its place over Cloggrum, as it lasts twice as long for the same mining level. It also enchants better, so if you’re somewhere cold enough to find Froststeel Ore, it’s the Iron level set to go for.
Froststeel
Froststeel Ore only generates in the Frostfields, the Frosty Smogstem Forest and the Icy Sea, so you’ll have to go looking for the cold biomes to find it. Smelt the 
Raw Froststeel into a 
Froststeel Ingot and make the gear the usual way.
A 
Froststeel Sword or Axe gives whatever you hit the Chilly effect for thirty seconds, which slows it down quite a lot, and the Pickaxe and Shovel give a weaker version of it. That makes Froststeel handy against the faster mobs, as you can hit them once and then keep them from running you down.
Utherium
Utherium Ore only generates deep down, from the bottom of the world up to y 32, and it’s rare, as a lot of the veins that end up touching air get removed. Mining it drops Utherium Crystals directly, and nine Utheric Shards from Rotspawn also craft into one, which is usually the quicker way to build up a stack.
A 
Utherium Sword or Axe does 50% more damage to Rotspawn, so it’s the weapon to have if you’re farming them for Shards. Utherium gear also smelts back down into a Crystal, which is handy for getting something back out of old tools once you move on to Forgotten gear.
Regalium
Regalium Ore is the deepest ore in the Undergarden, found from the bottom of the world up to around y 12. It drops 
Regalium Crystals, and you won’t use them for tools, as they’re the currency the Stoneborn trade in, which is covered in the next section.
Stoneborn Trading
The Stoneborn are big stone traders that wander the forests of the Undergarden. They’re neutral, so they won’t attack you unless you hit them first, and with 50 health and 10 damage per hit they’re a fight you’ll want to avoid. Right-click one to open its trades.
Each Stoneborn has four trades picked from a set list, and all of them use Regalium Crystals. You can sell Diamonds, Iron Ingots, Gold Ingots and Utherium Blocks for Regalium, or spend it on things like 
Blisterbombs, 
Shard Torches and 
Gloomgourd Seeds, which are the easiest way to get Gloomgourds growing.
| Trade | You Give | You Get |
|---|---|---|
| Sell | 1 Diamond | 12 Regalium Crystals |
| Sell | 1 Iron Ingot | 4 Regalium Crystals |
| Sell | 1 Gold Ingot | 2 Regalium Crystals |
| Sell | 1 Utherium Block | 48 Regalium Crystals |
| Buy | 16 Regalium Crystals | 8 Blisterbombs |
| Buy | 1 Regalium Crystal | 4 Shard Torches |
| Buy | 1 Regalium Crystal | 6 Gloomgourd Seeds |
| Buy | 32 Regalium Crystals | Music Disc |
Don’t try bringing a Stoneborn back to the Overworld with you. They only trade in the Undergarden, and if one ends up anywhere else it gets confused, starts chanting and explodes after about fifteen seconds, which isn’t something you’ll want going off next to your base.
Undergarden Mobs
Most of the danger in the Undergarden comes from the Rotspawn, which spawn in every biome, but there are plenty of passive and neutral creatures too. Some of them are worth hunting for food or materials, and one of them can even be ridden once you’ve found a Saddle.
Rotspawn
Rotlings, Rotwalkers and Rotbeasts are the rotting hostile mobs of the Undergarden, and they get tougher as they get bigger. A Rotling only has 10 health, a Rotwalker has 40, and a Rotbeast has 80 and hits for 10 damage, so the Rotbeast is the one to be careful with early on.
Rotspawn Drops
Utheric Shard Utheric Shard Utheric Shard They only drop Shards when a player gets the kill, so letting them fall into Lava or get killed by something else won’t give you anything. A Utherium Sword or Axe is the best thing to use on them once you have one, as it does half again as much damage to all three.
Dwellers
Dwellers are big passive creatures that live in the forests, and they work a lot like Pigs. Put a 
Saddle on one and you can ride it, then steer it with an 
Underbean on a Stick, which is the Undergarden’s version of a Carrot on a Stick.
You can breed Dwellers with 
Underbeans, and they drop 
Raw Dweller Meat and Leather when killed. The meat cooks into Dweller Steak, which makes Dwellers one of the better food sources in the Undergarden if you set up a small farm near your base.
Other Creatures
Gloompers are passive creatures that release clouds of Virulence every so often, which hurts you over time but can’t take you below one heart. Munchers drop Cloggrum and Froststeel Nuggets, Mogs and Sploogies drop Depthrock Pebbles, and Gwibs are dangerous fish that live in the Ancient Sea and Icy Sea.
Nargoyles and Brutes are the other things to watch for, as Nargoyles go after players and leap at you, and Brutes fight back hard if you hit one. Scintlings are small creatures that drop 
Goo Balls, which are useful as Slingshot ammo, so it’s worth picking them up rather than ignoring them.
The Slingshot
The Slingshot is the Undergarden’s ranged weapon, and it works like a Bow that fires whatever ammo you have in your inventory. Hold right-click to pull it back and let go to fire, and the longer a Depthrock Pebble stays in the air, the harder it hits when it lands.
| Ammo | Effect |
|---|---|
| Depthrock Pebble | Normal shot, more damage the further it flies |
| Rotten Blisterberry | Explodes on impact without breaking blocks |
| Goo Ball | Gives the Gooey effect |
| Gronglet | Sticks to the block it hits as a light |
Rotten Blisterberries are the ammo to save for groups, as they explode wherever they land but don’t damage any blocks. Depthrock Pebbles are the everyday ammo though, as you’ll pick up far more of them than you’ll ever use just from mining and killing Mogs.
Slingshot Enchantments
The Slingshot has three enchantments of its own. Longevity multiplies its durability, Ricochet makes shots bounce off blocks, and Self Sling turns it into a movement tool that launches you in the direction you’re looking, as long as you’re standing on the ground when you fire.
Self Sling doesn’t use any ammo at all, only durability, so it’s a handy way to cross gaps or climb out of a hole. It can send you a long way though, so be careful where you’re aiming, as a fall in the Undergarden is just as deadly as anywhere else.
The Catacombs
The Catacombs are the Undergarden’s main dungeon, a buried ruin full of the Forgotten, and they’re where the endgame starts. They generate in the Ancient Sea, Dense Forest, Forgotten Field, Gronglegrowth, Smogstem Forest and Wigglewood Forest biomes, spread out fairly evenly across the dimension.
Inside you’ll find the Forgotten, hostile mobs that spawn throughout the dungeon, along with Chests full of loot. The main reason to go in is the 
Forgotten Upgrade Smithing Template, which is needed for the Forgotten tools, and the chance of finding one is fairly low per Chest.
Catacombs Chest
Cloggrum Nugget 
Froststeel Nugget Utheric Shard 
Regalium Crystal 
Slop Bowl 
Cloggrum Sword 
Smithing Template 
Forgotten Nugget Check every Chest you come across, as each one has its own chance of a Template. Once you have one, you can copy it with seven Diamonds and a Depthrock block, so you only ever need to find a single Template to upgrade a full set of tools.
The Forgotten Guardian
The Forgotten Guardian is the Undergarden’s miniboss, and it’s found inside the Catacombs, guarding one of the tunnels. It has 80 health, 10 armor and hits for 10 damage, and it throws you back when it lands a hit, so you’ll want to keep your health topped up and fight it somewhere with room to move.
Arrows and Slingshot shots bounce straight off it, so this is a fight you have to do up close. It can’t be poisoned, slowed or given any other effect either, which rules out Froststeel’s Chilly effect and splash potions, so bring your best sword and good armor instead.
Forgotten Guardian Drops
Forgotten Nugget The Guardian drops between four and sixteen Forgotten Nuggets, and nine of them craft into a 
Forgotten Ingot. That’s the other thing you need for Forgotten gear, so you may have to find and kill a few Guardians to get enough Ingots for a full set of tools.
Forgotten Gear
Forgotten gear is the best in the Undergarden, and you make it by upgrading Cloggrum tools rather than crafting them from scratch. Put a Forgotten Upgrade Smithing Template, a Cloggrum tool and a Forgotten Ingot into a 
Smithing Table, and the Cloggrum tool turns into its Forgotten version.
2
Forgotten tools mine at Netherite level and mine Undergarden blocks half again as fast. The 
Forgotten Sword, Axe and 
Forgotten Battleaxe also do 50% more damage to anything from the Undergarden except bosses, which makes them the weapons to carry once you’ve got one.
Food and Potions
Food in the Undergarden mostly comes from farming and hunting what’s around you. 
Gloomgourds grow from seeds like Pumpkins, Underbeans grow on bushes and roast in a Furnace, and Dwellers and Gloompers both give meat that you can cook, so you won’t go hungry for long once you’ve found them.
Gloomgourd Pie is one of the better foods to aim for, made from a Gloomgourd, a mushroom and some Glitterkelp. Gloomgourd Seeds are also sold by the Stoneborn for a single Regalium Crystal, which is the quickest way to get a farm going if you haven’t found any growing wild.
| Ingredient (added to an Awkward Potion) | Potion |
|---|---|
| Blood Globule | Brittleness (take more damage) |
| Veil Mushroom | Featherweight (take more knockback) |
| Gloomgourd | Virulent Resistance |
| Droopfruit | Glowing |
Virulent Resistance is the one worth brewing, as it makes you immune to the Virulence from Gloomper clouds and the Virulent Mix in the bogs. Brittleness and Featherweight are harmful potions, so they’re more useful as splash potions to throw at mobs than anything you’d drink yourself.
Tips
Build your portal out of Stone Bricks near your Overworld base and bring plenty of Torches with you. The Undergarden is completely dark, and lighting up the area around your portal early stops you losing it and gives you a safe spot to come back to between trips.
Farm Rotspawn for Utheric Shards before you go hunting for Utherium Ore. The ore is rare and deep, while every Rotwalker and Rotbeast drops a handful of Shards, so a Utherium Sword usually comes faster from killing things than it does from mining.
Take a stack of Diamonds or Iron with you when you go looking for Stoneborn. Selling them is the easiest way to get Regalium, and the Gloomgourd Seeds and Shard Torches they sell are worth having early on, as both are hard to find any other way.
Go into the Catacombs with a full set of Utherium or Froststeel armor and a good sword. The Forgotten Guardian ignores anything you fire at it, so you can’t cheese it from range, and getting knocked back into a group of Forgotten is how most runs go wrong.
FAQ
Craft a Catalyst from four Gold Ingots, four Iron Ingots and a Diamond, then build a frame shaped like a Nether Portal out of Stone Bricks or Deepslate Bricks. Right-click the inside of the frame with the Catalyst to open the portal, and step through to go down to the Undergarden.
Check the frame first, as Cracked and Chiseled Stone Bricks don’t count, and the frame has to be a full rectangle. Check you’re clicking the empty space inside it, and that you’re in the Overworld, as the Catalyst won’t light a portal in the Nether or the End.
The Catacombs generate in the Ancient Sea, Dense Forest, Forgotten Field, Gronglegrowth, Smogstem Forest and Wigglewood Forest biomes. They’re a buried dungeon full of the Forgotten, and their Chests are where you’ll find the Forgotten Upgrade Smithing Template needed for the best gear.
Fight it up close, as arrows and Slingshot shots bounce off it and no potion effects work on it. It has 80 health and hits for 10, knocking you back, so wear Utherium or Froststeel armor, keep your health up and give yourself room so you don’t get thrown into other Forgotten.
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