BG3 Modding made easy.
It's not Netherese magic, but it might as well be.
Karsus Codex turns "wouldn't it be cool if..." into a Baldur's Gate 3 mod you can actually install. Describe the item, give it some magic, click build, download the file.
or describe it to your AI and let Forge Bot build it browse what other people built
No toolkit required · Exports a .pak
Tutorial video A typical Karsus Codex user makes their first item, ready to download, in about 10 minutes.
After the build
Want to share?
Play it yourself
Drop the .pak in your Mods folder and turn it on in the in-game Mod Manager.
How to install locally →Put it on Nexus Mods
The .pak uploads as-is. No repacking, no toolkit.
How to publish on Nexus Mods →Put it on mod.io
Import the .pak into the BG3 Toolkit, then upload from there.
How to use the BG3 Toolkit →Or skip the upload: make your items public and send friends to your creator page. Maybe they'll make something cool too.
New game mode
Progression items change the game.
A character shaped by what they found, not by the class table.
- Elixirs and tomes that buff your character for good: hit points, ability scores, proficiencies and expertise, spells, and more.
- Scatter them through chests, bookcases, bodies and vendors, act by act, or pick the spots yourself.
- Slow levelling down, leave it alone, or switch it off and let what you find be the whole ladder.
- Eldritch Blast at will
- +5 hit points permanent
- Expertise in Athletics permanent
- Fireball once per long rest