Numidium is a very simple mod manager for Bethesda games (for now only Skyrim) running with Proton on Linux.

It is not a mod manager in the sense that MO2 or Vortex are - it does not fix your load order, resolve dependencies or integrate with mod hosting platforms. It's more meant for people who like installing mods manually and have full control over the file structure logic, but don't want to pollute their Data directory. It allows you to keep your modlists as simple files and then instantly activate them without ever touching the base game directory, by simply mounting the combined virtual directory on top. The game executable sees a fully modded game, the real folder stays completely clean.

How to use

All numidium commands must be run as admin (e.g. with doas).

1. Put the numidium binary in your base game folder (the same where Data and the executable live)
2. Run numidium init in that same folder.
3. Extract the Data folder of a mod to a folder inside staging that represents this specific configuration of this mod, e.g. Numidium/staging/SeranaJihyoReplacer
4. Write a file for your modlist, ending in the extension .brass, in your lists folder. This file references each installed mod in order by its folder name. Lines that start with # are comments. Example:

epicimmersive.brass:

NAME Epic Immersive Modlist

INCLUDE skyrim_base_fixes

# npc stuff
STAGED SeranaJihyoReplacer
STAGED AllNPCsAreNeverland

# pretty nature
STAGED VeryCoolWater
STAGED AmazingTrees
STAGED FantasticPlants

skyrim_base_fixes.brass:

# base mechanics that we want in every modlist
STAGED NoFastTravel
STAGED PaperMap

5. Execute the binary from console: numidium mount epicimmersive
6. Play the game
7. Press Ctrl+C in the numidium console to unmount again.