How Karsus Codex Works
Create custom Baldur's Gate 3 items without touching the modding toolkit. Pick an item, add effects, download a ready-to-use .pak file.
Video tutorial coming soon
Step by Step
Choose a base item
Start with any weapon, armor, ring, amulet, or accessory from the game. We have hundreds of items in our catalog - from simple longswords to legendary artifacts.
Add recipes and effects
Apply pre-built recipes like elemental damage, stat bonuses, or special abilities. Or use the custom effects builder to add specific passives from the game.
Build and download
Click "Build Mod" and we generate a .pak file ready to drop into your game. No toolkit installation, no XML editing, no UUID management.
Installing Your Mod
Drop the .pak file into your BG3 Mods folder:
%LOCALAPPDATA%\Larian Studios\Baldur's Gate 3\Mods
~/Library/Application Support/Larian Studios/Baldur's Gate 3/Mods
Then enable it in your mod manager (Vortex, BG3 Mod Manager, or the in-game mod menu). Your custom item will appear in a tutorial chest near the Nautiloid starting area.
Recipes vs Custom Effects
Recipes
Pre-built effect packages that are tested and balanced. Great for common modifications.
- Elemental damage conversions
- Stat bonuses (+STR, +DEX, etc.)
- Weapon enchantments
- Armor effects
Custom Effects
Direct access to game passives. More powerful but requires knowing what you want.
- Arcane Acuity, Arcane Synergy
- Burning Fury, Cat's Grace
- Any passive from the game
- Searchable catalog
Tips for Good Mods
- Start simple: Add one or two effects first, test in-game, then iterate.
- Check compatibility: Some effects only work on certain item types (weapon-only, armor-only, etc.).
- Use the tutorial chest: Your items spawn there - no need to use console commands.
- Version your mods: Each rebuild creates a new version you can compare.
- Share your creations: Make your mod public so others can use or remix it.