The Underworld, also known as Hell, is the bottommost Biome in the game, reached by digging past the Stone Layer. The Underworld can easily be differentiated from other biomes due to the background wall changing to a lava vein pattern.
The Underworld contains mostly intact buildings called Underworld Houses, which may contain Pots, Hellforges, and any kind of chest. Prior to 1.2, these houses were frequently very damaged or partially complete. The Underworld is the only biome where Hellstone, Ash Blocks, Hellforges, Fireblossoms, Shadow Chests, and others may be found. Healing Potions can be found in Pots instead of the Lesser Healing Potions that tend to be found in other areas. Additionally, it contains stronger enemies than most other pre-hardmode biomes.
The Underworld begins at around 1000-1500 on small worlds, 3000-3200 feet on medium-sized worlds and around 5000 feet on large worlds, but it may start at around 2000-2500 feet in medium worlds in some instances.
|Bone Serpent||Able to travel through lava and all blocks (except air).||250|
|Demon||Fires Demon Scythes at a player.||120|
|Fire Imp||Can shoot Fireballs through blocks at a player, which can be blocked with any attack.||70|
|Hellbat||A Underworld version of the Cave Bat.||46|
|Lava Slime||Behaves as a a regular slime, but it can swim in lava without being harmed.||50|
|Voodoo Demon||Just like a regular Demon; drops the Guide Voodoo Doll when killed, which will summon the Wall of Flesh if it falls or is dropped into Lava.||140|
|Red Devil (Hardmode)||Similar to the Demon, but fires much more powerful tridents, and it also has more health.||600|
|Lava Bat (Hardmode)||An upgraded version of the Hellbat, but is slightly more powerful and has more health than the Hellbat.||160|
|Arch Demon (Console and Android)||Essentially the same as a standard Demon, but shoots more Demon Scythe projectiles at a time, spawns less frequently, and does not drop the Demon Scythe spell.||120|
|Wall of Flesh||This is a summonable boss (Toss a Guide Voodoo Doll into lava to summon).|
See Wall of Flesh article for details.
Reaching the Underworld
Early game, you will find that as you explore caves deeper and deeper, you will eventually hit The Underworld. This, however, is not very effective as if you wish to frequently revisit The Underworld; it may take 5-10 minutes traversing the caves to reach the Underworld.
Once you have the time and resources, it is well worth the time to make a Hellevator. This is essentially a 2 block wide hole that goes all the way down to The Underworld, allowing you to jump in and wait as you fall all the way down.
- Note: If you don't have a fall damage negating item such as Wings or a Lucky Horseshoe, make sure to place a few blocks of water at the bottom so as that you don't take any fall damage. However, you should be sure to end it right before the Underworld, since water in the Underworld evaporates.
While it is debatable whether it is worth the time and money, a Teleporter from your house to The Underworld is by far the fastest way to get down there. However, depending on the world size, this can cost several platinum coins.
There are several items that are highly recommended to bring whenever you visit The Underworld.
- Cloud in a Bottle/Balloon (or other double-jumping items) and/or Rocket/Spectre Boots
- The Underworld is filled with large pockets of lava that can be difficult to get over without the assistance of a double jump and or boost.
- Grappling Hook
- Very useful for a quick save, to avoid taking a dip in the lava pools, as well as getting you out of them as quickly as possible. It's also useful for getting over those large pockets of lava mentioned earlier.
- Obsidian Skull/Horseshoe/Shield
- Lava Waders
The only ore available in the Underworld is Hellstone, which is used to create Molten Armor and other molten items, which is the highest tier of armor and tools available before activating Hard Mode. Upon contact with Hellstone ore, the player will receive fire damage, which can only be prevented by equipping an Obsidian accessory, like the Obsidian Skull, Obsidian Horseshoe, Obsidian Shield, Water Walking Boots (the latter three are created by tinkering the original items with the Obsidian Skull at a Tinkerer's Workshop), and drinking the Obsidian Skin Potion.
The most important thing to note is that mining Hellstone will spawn approximately half a tile of lava for every block mined out. As such, it is advisable to always keep at least a one-block-thick wall of blocks between oneself and the ore being mined. Ash Blocks are found abundantly throughout the Underworld and will serve very well for this purpose. If attempting to mine around smaller lava pockets, it is best to dig out additional sections in order to cause the lava to flow elsewhere, out of the way, rather than attempting to tunnel through it in any fashion.
Always keep at least a one-block-thick wall between oneself and any lava pockets or ore deposits being mined to avoid being surprised by a sudden lava flow, and ending up dead.
- Placing 50 Meteorite will stop underworld monsters from spawning, and replace them with Meteor Heads.
- It's highly recommended for players to take Obsidian Skin Potions or Water Walking Potions to avoid lava damage.
- The very bottom of the Underworld has an invisible boundary like the far left, right and very top of the map. Touching this invisible barrier will give the "Rock Bottom" achievement.
- Fireblossom, Daybloom, Waterleaf, and Blinkroot can grow in The Underworld. It may be possible for Moonglow and Deathweed to grow as well.
- The Underworld is the only biome where Hellfire Arrows and Shadow Chests (a rare chest that contains rare items) may be found.
- When you start traveling along the Underworld, leaving the area with the houses and closer to the edges, the spawn rate of monsters gets noticeably higher. This is because the majority of the monsters spawn either in lava (Slimes) or in empty space (Demons and Hellbats).
- The amount of Lava in the Underworld isn't infinite, so it's theoretically possible to remove all the lava down there by turning it into Obsidian if you've got sufficient supply of Water.
- Any water left stagnant in pools will evaporate in the Underworld, and although a glitch makes it possible to have pools, removing blocks around the water will cause it to evaporate.
- Heart Crystals are far easier to find in The Underworld than in other Environments.
- It's possible to encounter Underworld Monsters from the Cave layer or from the Underground Jungle.
- You can find it easier with a Depth Meter or GPS.
- In the Console Version, Hellforges will spawn in the lowest areas of The Underground rather than in the Underworld itself. (Fixed, they now spawn in the correct place.)
- Previously, the Underworld ironically became easier than the other biomes in Hardmode due to the lack of new monsters in Hardmode. As of 1.3, the Red Devil is the only monster added, but it deals significant damage and is more difficult to fight. Additionally, the Corruption and Hallow both intersect in the Underworld after the Wall of Flesh is destroyed.
- The new background and music in v126.96.36.199 do not remove the original 2 backgrounds. According to looking at it, it might have pushed up to the lower cavern. This does not count the area where lava starts. So you should be lucky it's still there but higher.
- New Background and Music.
- Any monster in The Underworld after the Wall of Flesh has been defeated will now have a chance to drop Living Fire Blocks.
- Underground Houses have been completely redesigned and now feature furniture, paintings, banners and doors.
- Underworld Houses can now be made from Obsidian Brick.
- Water now evaporates once it reaches The Underworld.
- Decreased spawn rate of monsters.
- New monsters added.
- Increased spawn rate of monsters.
- Added to the game.