Citadel Mod (1.21.1, 1.20.1) – A Lightweight Library

Citadel is a lightweight library mod that provides advanced entity animations, model loading, and mob property tracking for Minecraft Forge and NeoForge. Created by AlexModGuy, it serves as the essential backbone for many popular creature and wildlife mods.

Anyone who has tried installing a popular creature mod for Minecraft has likely encountered the frustrating "missing dependency" error that points straight to Citadel. That is because Citadel quietly powers some of the most beloved mods in the ecosystem, handling the complex animation and entity systems that bring custom mobs to life. With over 10 million downloads on Modrinth alone, Citadel has become one of the most widely installed library mods in the Minecraft modding community — and for good reason. It solves a fundamental problem: without a shared framework for animations and entity data, every mob mod would need to reinvent the wheel, leading to conflicts and bloated file sizes. Citadel handles all of that in one compact package.

Key Features of Citadel Mod

• Advanced Entity Animation Framework — Citadel provides a complete animation system that mod developers use to bring custom creatures to life. This means smoother, more realistic mob movements compared to what vanilla Minecraft offers. Players benefit directly because the mods they love — like Alex's Mobs — rely on this system for their detailed creature behaviors.
• Tabula (.tbl) and Wavefront (.obj) Model Loading — The library supports loading models in both Tabula and Wavefront formats, giving developers flexibility in how they design custom entities. For players, this translates to higher-quality mob models with more detail and variety. It also means developers can iterate faster, which leads to more frequent mod updates.
• Entity Property Tracking — Citadel keeps track of custom properties attached to entities, allowing mods to store and retrieve data about individual mobs efficiently. This is what enables features like taming progression, custom health scaling, and unique creature behaviors across dependent mods.
• Mob Spawn Cap Configuration — Starting from version 1.6.3, Citadel includes a config option to adjust the cap on how many mobs spawn during chunk generation. This is particularly valuable when you run multiple creature mods simultaneously, as the default spawn cap can make vanilla mobs nearly impossible to find in heavily modded worlds.
• Successor to LLibrary — Citadel replaced the older LLibrary starting from Minecraft 1.14, carrying forward its proven codebase with permission from the original maintainers. Players upgrading from older modpacks no longer need LLibrary, and the transition to Citadel ensures continued support and active development on modern Minecraft versions.
• Lightweight Footprint — As a library mod, Citadel appears to be lightweight and does not add visible content to the game on its own. It runs quietly in the background, providing its services only when other mods call upon them, so it should not noticeably affect load times or performance for most setups.
• Open Source Under LGPL-3.0 — The entire codebase is available on GitHub, meaning the community can inspect, contribute to, and verify the code. This transparency gives players and developers confidence in the mod's safety and long-term sustainability.

Screenshots

How to Install Citadel Mod

1. Download and install Minecraft Forge or NeoForge for your Minecraft version. For 1.21.1, NeoForge is required; for 1.20.1 and earlier, either loader works.
2. Download the correct Citadel file for your Minecraft version from the download section below. Make sure the version matches your loader and game version exactly.
3. Open your Minecraft installation folder and navigate to the mods folder. If it does not exist, launch the game once with Forge or NeoForge to generate it automatically.
4. Place the downloaded Citadel .jar file into the mods folder. Then add any mods that depend on Citadel — such as Alex's Mobs or Ice and Fire — into the same folder.
5. Launch Minecraft using your Forge or NeoForge profile. If everything is installed correctly, Citadel will load silently in the background without any additional configuration needed.

Requirements & Compatibility

What's New

• Official release for Minecraft 1.21.1 with NeoForge support
• Fixed a server-side memory leak related to world data loading, improving stability for dedicated servers
• Continued maintenance and compatibility updates for the latest Minecraft versions

Pros and Cons

Alternatives to Citadel Mod

• GeckoLib — A popular animation library for Minecraft mods that supports Forge, NeoForge, and Fabric, offering a broader loader compatibility for developers building animated entities.
• Architectury API — A cross-platform library that helps mod developers write code compatible with both Forge and Fabric, useful for projects that need multi-loader support beyond what Citadel provides.
• PlayerAnimator — A specialized animation library focused on player model animations, complementing Citadel's entity-focused animation system for modpacks that need both.

Download Citadel Mod

Always download mods from official sources to stay safe.

Frequently Asked Questions

Is Citadel required for Alex's Mobs?

Yes — Citadel is a mandatory dependency for Alex's Mobs and must be installed for that mod to function. Alex's Mobs relies on Citadel's animation framework and entity property system to render and manage all of its custom creatures. Without Citadel, the game will crash or refuse to load when Alex's Mobs is present in your mods folder.

Does Citadel work on Fabric?

No — Citadel is only available for Minecraft Forge and NeoForge. There is no official Fabric or Quilt port of the mod. If you are using Fabric, you will need to check whether the mods you want have alternative dependencies that support that loader.

Does Citadel add any content to the game?

No — Citadel is a library mod that runs entirely in the background. It does not add blocks, items, mobs, or any visible content on its own. Its purpose is to provide shared code and systems that other mods use, particularly for entity animations and model loading.

Can I adjust mob spawn rates with Citadel?

Yes — starting from version 1.6.3, Citadel includes a configuration option to change the mob spawn cap during chunk generation. This setting is especially helpful when you have several creature mods installed, as the combined mob spawns can crowd out vanilla animals and monsters. You can find this option in Citadel's config file within your Minecraft configuration folder.

Is Citadel safe to install on a multiplayer server?

Yes — Citadel is open source under the LGPL-3.0 license, and its code is publicly available on GitHub for anyone to review. The latest update also fixed a server-side memory leak related to world data loading, so running the newest version is recommended for dedicated servers. Both the server and all connecting clients need to have the same version of Citadel installed.

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