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.