# bethesda
> Bethesda games: Fallout 3, Fallout: New Vegas, Fallout 4, Oblivion, Oblivion Remastered, Skyrim (LE/SE/AE/VR).

## Identity
Bethesda is the studio behind The Elder Scrolls and Fallout. These games are extremely moddable and share one pattern: plugin files (`.esp/.esm/.esl`) and archives in `Data/`, a `plugins.txt` load list, a script extender, and community tools (xEdit, LOOT, Mod Organizer 2 or Vortex, Wrye Bash). Always confirm WHICH game and WHICH edition/version the user has: mods and script extenders are version-locked.

| Game | Engine | Script extender | Plugins / archives | Notes |
|---|---|---|---|---|
| Fallout 3 | Gamebryo | FOSE | .esp/.esm, .bsa | archive invalidation; FO3Edit; some mods need the 4GB fix |
| Fallout: New Vegas | Gamebryo | NVSE | .esp/.esm, .bsa | separate from FO3; FNVEdit; many mods need NVSE + 4GB patcher |
| Fallout 4 | Creation Engine | F4SE | .esp/.esm/.esl, .ba2 | archive invalidation in Fallout4Custom.ini; updates break F4SE/DLL mods |
| Oblivion (2006) | Gamebryo | OBSE | .esp/.esm, .bsa | Wrye Bash/BAIN; TES4Edit; ArchiveInvalidation via INI |
| Oblivion Remastered (2025) | Unreal Engine 5 front end over original game logic | UE4SS | .esp/.esm and .pak | different layout, see below |
| Skyrim (LE/SE/AE/VR) | Creation Engine | SKSE (separate build per edition) | .esp/.esm/.esl, .bsa | SKSE and Address Library DLL mods must match the exact exe version |

## Mod folder and format (all but Oblivion Remastered)
Mod contents merge into `<game>/Data/`. Script extender files go in the game root next to the .exe, NOT in `Data/`. Enable plugins via the manager or `%LOCALAPPDATA%/<Game>/plugins.txt`. Prefer Mod Organizer 2 or Vortex over manual installs for many mods, with the right game edition selected.

## Oblivion Remastered layout (Steam and Game Pass folder names differ: check which)
- `.esp/.esm` -> `OblivionRemastered/Content/Dev/ObvData/Data/`, then add the plugin name to `Plugins.txt` in that same folder.
- `.pak` mods -> `OblivionRemastered/Content/Paks/~mods/` (create `~mods` if missing). Paks are not sortable in a load-order UI.
- UE4SS -> `OblivionRemastered/Binaries/Win64/` (Game Pass: `WinGDK`); Lua/UE4SS mods -> `.../ue4ss/Mods/`, enabled via `mods.txt`.
- Vortex has a dedicated extension. Do not mix classic Oblivion mods/tools (OBSE etc.) with Remastered, or the reverse.

## Sources
Nexus Mods first (each game has its own Nexus page: do not mix FO3 and New Vegas, or Skyrim LE and SE), then GitHub Releases for script extenders (or their official sites). Verify current versions with web_search.

## Compatibility checks before deploying
Exact game and edition; script extender installed and matching the game version; master files (`.esm`) present for every plugin; plugin count limits (light `.esl` where supported); LOOT sort afterwards; read each mod's requirements for patch/compat plugins.

## Load order
`plugins.txt` + LOOT; xEdit to resolve conflicts and find missing masters.

## Logs
Script-extender logs (SKSE, F4SE, NVSE, FOSE, OBSE; usually `Documents/My Games/<Game>/...` or the game root), crash-logger output if installed, xEdit and LOOT reports. Oblivion Remastered: `UE4SS.log` in `Binaries/Win64`. Use the `log-debugging` module.

## Common failures
Missing master -> install the required mod or disable the plugin. Script extender version mismatch after a game update -> install the matching build or downgrade the game. Wrong edition mods (SE mod on LE, etc.) -> crash at load.