YUNG's Better Nether Fortresses

Overview

YUNG's Better Nether Fortresses is a complete structural overhaul that replaces every vanilla Nether Fortress in your world with a far more ambitious and detailed design. The new fortress is divided into three interconnected sections: the Keep, the Bridge Networks, and the Lava Halls. Each section has its own architectural style, its own loot tables, and its own dangers. The structure spawns in all Nether biomes with a spacing of 30 chunks and a minimum separation of 20 chunks between fortresses.

This mod does not add any new items, blocks, or crafting recipes. Instead, it focuses entirely on reimagining the Nether Fortress as a sprawling, multi-level dungeon filled with themed rooms, unique loot, and more challenging encounters. The mod requires YUNG's API as a dependency and also features built-in compatibility with the Create mod.

The Three Sections

The Keep

The Keep serves as the central hub and starting anchor point of every fortress. It is the largest single structure in the fortress, featuring an imposing interior with a towering Wither statue and Soul Lanterns providing eerie illumination. The Keep contains multiple Chests with a loot table focused on combat gear: Stone, Iron, and Golden Swords (some enchanted), Leather, Chainmail, and Golden armor pieces, Horse Armor, and Saddles. Higher-tier enchanted gear has a chance to appear with up to level 30 enchantments on Golden equipment.

The Keep is divided into three sub-sections: a central well area and two side wings (left and right). This gives the Keep a symmetrical, imposing appearance. When the Create mod is detected, the fortress may generate with a special Create-compatible variant of the Keep that includes mechanical doors powered by Create mechanisms.

The Bridge Networks

The Bridge Networks form the upper level of the fortress, stretching across the Nether at Y=31 and above. These are expanded and more detailed versions of the vanilla fortress bridges, supported by massive pillars that extend down to the Lava below. Bridges connect through junctions of varying complexity, from simple two-way corridors to sprawling four-way intersections.

Several special features can appear along the bridges. Beacon towers, both lit and unlit, occasionally generate on bridge pillars (roughly 4-8% chance per eligible pillar). Shelters, small covered rest stops with potential loot, appear on about 20% of eligible pillars. Some bridge sections spawn in ruined variants, giving the fortress a weathered and ancient feel. Blaze Spawner platforms connect to the bridges via dedicated staircases and serve as the primary source of Blaze Rods during your exploration.

The Lava Halls

The Lava Halls are the sprawling underground portion of the fortress, extending deep below the bridge level. This is where the fortress truly shines in terms of variety. The halls consist of long corridors with straight sections, three-way and four-way intersections, turns, and staircases connecting different levels. Rooms branch off from the main corridors and come in small, medium, and large sizes, each with a unique theme and purpose.

Room Types

The Lava Halls contain over a dozen distinct room types, each with unique decorations and purposes. Rooms are limited in how many times they can appear per fortress, ensuring variety across every exploration.

Small Rooms

Quarters are compact sleeping areas that can appear up to twice per fortress. They contain Chests with Gold Nuggets, Gold Ingots, Raw Gold, Quartz, Magma Cream, Fire Charges, and the occasional Diamond. Officer Rooms are similar in size but with more refined decoration, also limited to two per fortress. Storerooms come in two variants and serve as supply caches, appearing up to twice. The Study is a small library-like room (limited to one) with Item Frames that may contain Books, Paper, Writable Books, or Enchanted Books.

Medium Rooms

The Mess Hall is a dining area limited to one per fortress, decorated with Item Frames containing Porkchops, Cooked Porkchops, and Gold Ingots. The Study (medium variant) is a larger library room, also limited to one. Jail cells feature Iron Bar enclosures and appear at most once. Worship Rooms are shrines dedicated to the Wither, containing valuable loot including Iron and Gold Ingots, Nether Wart, and Diamonds, limited to one per fortress.

The Nether Reactor Room is a unique chamber referencing Minecraft's legacy Nether Reactor Core, limited to one. The Alchemy Room contains brewing-themed decorations with Item Frames holding Quartz, Magma Cream, and Fire Charges, and is guaranteed to appear once per fortress due to its priority flag. The Armory features weapon displays and combat-themed loot, appearing at most once. The Obsidian Room contains Chests with Obsidian, Crying Obsidian, Flint and Steel, and Diamonds.

Large Rooms

The Better Portals Room is the largest room type in the Lava Halls. This massive chamber is limited to one per fortress and has strict generation requirements, only appearing between Y=4 and Y=30. It serves as a dramatic centerpiece for the underground section of the fortress. The room is given high priority weight (20), meaning the generation system will actively try to place it when conditions are met.

Mob Spawns

The redesigned fortress maintains all of the hostile mobs you would expect to find in a Nether Fortress, but with adjusted spawn weights and group sizes. Blazes are the most common spawn with a weight of 10, appearing in groups of 2-3. Wither Skeletons have a weight of 8 and spawn in larger packs of 5, making them a significant threat throughout the structure. Zombified Piglins appear with a weight of 5 in groups of 4, while Magma Cubes have a weight of 3 in groups of 4. Regular Skeletons can also spawn with a weight of 2 in groups of 5.

The mob spawning system uses piece-based bounding boxes, meaning mobs will only spawn within the actual structure pieces rather than in a large bounding box around the fortress. The mod also includes a fix that ensures fortress mob spawning works correctly on Nether Brick blocks within the new structure, matching vanilla behavior.

Loot Tables

The mod introduces nine distinct loot tables, each tied to a specific area or room type within the fortress. This means different sections reward exploration with different types of treasure, giving you a reason to seek out every corner of the structure.

Keep Chests

The Keep's loot table is focused on combat equipment. Each chest rolls 2-4 items from a table that includes Stone, Iron, and Golden Swords (plain or enchanted), full sets of Leather, Chainmail, and Golden armor, Horse Armor in Iron, Gold, and Diamond tiers, and Saddles. Enchanted variants can have levels up to 10 (Leather/Stone), 20 (Chainmail/Iron), or 30 (Golden). All weapons and armor spawn with random durability between 10-80%.

Storage Room Chests

The Storage Room is the single most valuable loot location in the fortress. Each chest rolls 3-6 items including Iron Nuggets, Gold Nuggets, Iron Ingots, Gold Ingots, and Nether Wart. On top of that, every Storage Room chest is guaranteed to contain a Blaze Rod. This makes the Storage Room a critical target if you need Blaze Rods but want to avoid farming Blaze Spawners. It also has a chance to contain 1-2 Diamonds.

Worship Room Chests

Worship Rooms contain 3-6 items per chest, drawing from Iron and Gold Nuggets and Ingots, Nether Wart, and Diamonds. The loot quality here is comparable to Storage Rooms but without the guaranteed Blaze Rod.

Beacon Tower Chests

Beacon towers along the bridges contain ranged combat supplies. Each chest provides 2-4 Arrows or 2-3 Fire Charges, plus a guaranteed Bow. Bows can spawn plain, with level 10 enchantments, or with level 20 enchantments. These are excellent early finds for players who prefer ranged combat in the Nether.

Obsidian Room Chests

The Obsidian Room contains 2-5 Obsidian and 1-3 Crying Obsidian, plus a chance at a Flint and Steel or Diamond. This room is invaluable if you need to build a return portal and lost your Flint and Steel.

Other Chest Types

Hall chests provide basic supplies like Iron and Gold Nuggets, Iron Ingots, Gold Ingots, Leather, String, and Glowstone Dust. Quarters chests lean toward Gold-themed loot with Gold Nuggets, Gold Ingots, Raw Gold, Quartz, and a chance at Magma Cream, Fire Charges, or Diamonds. Extra chests found throughout the structure provide a general mix of metals, Leather, String, Glowstone Dust, and Quartz.

Item Frames

Certain rooms in the fortress feature Item Frames with themed contents that add to the atmosphere and provide small bonuses. The items in these frames are determined by the room type. Weapon displays can contain Stone, Iron, or Golden Swords and Axes, Shields, and rarely a Netherite Sword (0.5% chance). Study rooms have frames with Books, Paper, Writable Books, and Enchanted Books. Mess Hall frames contain food items like Porkchops and Gold Ingots. Alchemy rooms display Quartz, Magma Cream, and Fire Charges. General loot frames hold Gold Nuggets, Gold Ingots, or Nether Wart.

The item frame probabilities are fully configurable through a JSON file. The mod generates an itemframes.json file in your config/betterfortresses/ directory where you can customize every item and its probability for each room category.

Configuration

The mod has a single config option in its main config file (betterfortresses-neoforge-1_21.toml): the ability to toggle whether vanilla Nether Fortresses are disabled. This is set to true by default, meaning vanilla fortresses will not generate at all. If you want both vanilla and Better Fortresses to coexist in your world, set "Disable Vanilla Nether Fortresses" to false. Note that changing this option requires a world restart to take effect.

For more advanced customization, the mod creates a config/betterfortresses/neoforge-1_21/ directory containing an itemframes.json file. This file lets you customize the probability distribution of items in Item Frames throughout the fortress. Each category (weapons, loot, study, mess hall, alchemy) can be independently configured with custom items and weights. The total probability for each category should not exceed 1.0, with any remaining probability defaulting to Air (empty frame).

The fortress spawn rate and placement can be modified via data pack by overriding the structure set at betterfortresses:fortress. The default spacing is 30 chunks with a separation of 20 chunks.