FromSoft Mod Manager

Skip the manual mod setup headaches — FromSoft Mod Manager automatically finds your Steam games, installs co-op mods from Nexus with one click, and keeps everything up to date. Connect your Nexus account, pick your game, and you're playing co-op in minutes. Saves, settings, and mod loading through Mod Engine 3 are all handled for you.

Note: This is a manager tool only. The Seamless Co-op mods are created by LukeYui. All credit for the mods goes to them.

Game launching and mod loading is powered by Mod Engine 3 by Gary Tierney.

Quick install: Download the installer from the latest Release and run it.

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Supported Games

Game	Co-op Mod	Nexus Mods
Armored Core 6: Fires of Rubicon	AC6 Seamless Co-op	Nexus page
Dark Souls Remastered	DSR Seamless Co-op	Nexus page
Dark Souls III	DS3 Seamless Co-op	Nexus page
Elden Ring	Elden Ring Seamless Co-op	Nexus page
Elden Ring Nightreign	ER Nightreign Seamless Co-op	Nexus page
Sekiro: Shadows Die Twice	— (ME3 mod loading only)	Nexus page

The app auto-detects installed Steam games by scanning all library folders across all drives.

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Features

Mod Management

• One-click install from Nexus Mods — paste a URL or browse trending/recommended mods
• Automatic update checking against Nexus Mods versions
• Enable/disable individual mods via toggle switches
• Archive support — .zip, .7z, and .rar mod archives
• Progress tracking — download and install progress shown in-dialog
• Add third-party mods by pasting a Nexus URL or selecting a local archive

Mod Engine 3 Integration

• Generates and manages ME3 TOML profiles per game
• Structured profile viewer showing native DLLs and asset packages
• Collapsible raw TOML view for power users
• Games launched via ME3 for proper DLL injection and asset loading
• Auto-downloads ME3 on first launch if not installed

Nexus Mods Integration

• OAuth 2.0 authentication — click "Authorize with Nexus Mods", approve in browser, done (no copy-paste needed)
• Automatic token refresh — stays connected across sessions
• User profile display in sidebar
• Trending and recommended mods per game
• Direct download with Nexus Premium support

Mod Settings

• Edit mod .ini settings through a clean dialog UI
• Smart type inference — dropdowns, number fields, and text inputs based on INI comments
• Change highlighting and save confirmation
• Reset to defaults

Save Manager

• View base game saves (.sl2) and co-op saves (.co2)
• Transfer saves between base and co-op formats
• Backup and restore with timestamps
• Ban risk warnings for co-op-to-base transfers

Game Launching

• Launch via Mod Engine 3 with all mods loaded
• Fallback to direct co-op launcher for non-ME3 games
• Error detection via ME3 log file checking
• Desktop shortcut creation
• Live Steam player counts (refreshes every 60 seconds)

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Installation

Prerequisites

• Windows 10/11 (64-bit)
• Steam with at least one supported game installed
• Mod Engine 3 — the app will download and install it automatically on first launch
• Nexus Mods account — required for downloading and updating mods (create a free account)

From Release (Recommended)

1. Download FromSoftModManager_Setup_v*.exe from the latest GitHub Release
2. Run the installer — it installs to %LOCALAPPDATA%\FromSoftModManager
3. Launch from Start Menu or desktop shortcut
4. On first launch, the app will prompt to install Mod Engine 3 if not found

From Source (Development)

git clone https://github.com/spikehockey75/FromSoftSeamlessCoOpManager.git
cd FromSoftSeamlessCoOpManager
python -m venv .venv
.venv\Scripts\pip install -r requirements.txt
.venv\Scripts\python main.py

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Building the Installer

Building the distributable .exe installer is a two-step process:

Step 1: Build the app with PyInstaller

.venv\Scripts\python build\build.py

This runs PyInstaller and outputs the bundled app to dist/FromSoftModManager/. The build script:

• Bundles all Python code, PySide6, and dependencies into a single directory
• Includes the resources/ folder (theme, cover art, logos) and VERSION file
• Produces dist/FromSoftModManager/FromSoftModManager.exe

Step 2: Create the installer with Inno Setup

1. Install Inno Setup 6+ (free)
2. Open build/installer.iss in Inno Setup
3. Click Build > Compile (or press F9)
4. The installer is created at dist/FromSoftModManager_Setup_v2.0.0.exe

The installer:

• Installs to %LOCALAPPDATA%\FromSoftModManager (no admin required)
• Creates Start Menu and optional desktop shortcuts
• Includes an uninstaller
• Prompts to download ME3 if not already installed

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How to Use

First Launch

1. Open the app — it will prompt to install Mod Engine 3 if needed
2. Click Scan Games in the sidebar — scans all drives for Steam libraries and games
3. Detected games appear in the sidebar with live player counts

Connecting Nexus Mods

1. Click Connect Account in the sidebar
2. Click Authorize with Nexus Mods — your browser opens
3. Click "Authorize" on the Nexus page — the app connects automatically
4. Your Nexus username appears in the sidebar

Managing Mods

• Mods tab — install, update, enable/disable mods; browse trending mods
• ME3 Profile tab — view the ME3 mod loading configuration (ME3-supported games only)
• Saves tab — manage save files, backups, and transfers

Adding Mods

• Click Add Mod → paste a Nexus Mods URL (e.g., https://www.nexusmods.com/eldenring/mods/510)
• Or select a local .zip / .7z / .rar archive
• Progress bar shows download and install status

Launching Games

Click the Play button in the sidebar. Games with ME3 support are launched via Mod Engine 3 for proper mod loading.

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Project Structure

fromsoft_coop_manager/
├── main.py                      Entry point
├── VERSION                      App version string
├── requirements.txt             Python dependencies
├── app/
│   ├── config/
│   │   ├── config_manager.py    Config wrapper (config.json)
│   │   └── game_definitions.py  Game metadata, paths, and defaults
│   ├── core/
│   │   ├── game_scanner.py      Steam library scanner
│   │   ├── ini_parser.py        INI file parser with type inference
│   │   ├── me2_migrator.py      Mod Engine 2 → ME3 migration
│   │   ├── me3_service.py       ME3 CLI integration
│   │   ├── mod_installer.py     Archive extraction and mod install
│   │   ├── mod_updater.py       Version comparison and updates
│   │   └── save_manager.py      Save file operations
│   ├── services/
│   │   ├── nexus_service.py     Nexus Mods REST API client
│   │   ├── nexus_oauth.py       Nexus OAuth 2.0 PKCE auth flow
│   │   └── steam_service.py     Steam player count and asset APIs
│   └── ui/
│       ├── main_window.py       Main window with sidebar + content
│       ├── sidebar.py           Game list, player counts, Nexus
│       ├── game_page.py         Per-game tab container
│       ├── nexus_widget.py      Nexus auth widget (OAuth 2.0)
│       ├── terminal_widget.py   Log output panel
│       ├── tabs/
│       │   ├── launch_tab.py    Game launcher with cover art
│       │   ├── mods_tab.py      Mod cards, trending, install
│       │   ├── saves_tab.py     Save file management
│       │   └── settings_tab.py  ME3 profile viewer
│       ├── dialogs/
│       │   ├── add_mod_dialog.py      Add mod via URL or archive
│       │   ├── confirm_dialog.py      Confirmation prompts
│       │   ├── me2_migration_dialog.py  ME2 migration wizard
│       │   ├── me3_setup_dialog.py    First-launch ME3 installer
│       │   ├── mod_settings_dialog.py INI settings editor
│       │   └── settings_dialog.py     App settings
│       └── widgets/
│           └── toggle_switch.py  Animated toggle switch widget
├── resources/
│   ├── dark_theme.qss           Qt stylesheet (dark theme)
│   ├── covers/                  Steam cover art cache
│   ├── headers/                 Steam header image cache
│   ├── logos/                   Steam logo cache
│   └── icons/                   App icons
└── build/
    ├── build.py                 PyInstaller build script
    └── installer.iss            Inno Setup installer config

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Dependencies

Package	Purpose
PySide6	Qt 6 UI framework
requests	HTTP client for API calls
tomlkit / tomli-w	TOML reading/writing for ME3 profiles
py7zr	7z archive extraction
rarfile	RAR archive extraction (requires WinRAR or 7-Zip)
pyinstaller	Build tooling (dev only)

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FAQ

Can I get banned for using this?

No. The co-op mods prevent you from connecting to FromSoftware's matchmaking servers and use separate save files. There is no risk of bans from normal use.

Do not transfer co-op save files back to base game saves and then play online — this risks a ban.

The app didn't find my game

• Make sure the game is installed via Steam
• Click Scan Games to re-detect
• The co-op mod does not need to be pre-installed — you can install it from the Mods tab

RAR mods fail to extract

RAR extraction requires WinRAR or 7-Zip to be installed on your system. The app checks these default paths:

• C:\Program Files\WinRAR\UnRAR.exe
• C:\Program Files\7-Zip\7z.exe
• C:\Program Files (x86)\ variants

Can I add support for another game?

Add a new entry to GAME_DEFINITIONS in app/config/game_definitions.py and (if ME3-supported) add the game to ME3_GAME_MAP in app/core/me3_service.py.

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Technical Details

Component	Details
UI Framework	PySide6 (Qt 6) with Fusion base style
Mod Loader	Mod Engine 3 CLI (me3 launch -g <game>)
Nexus Auth	OAuth 2.0 PKCE with automatic token refresh
Packaging	PyInstaller (onedir) then Inno Setup installer
Config	JSON config file (config.json)
Theme	Custom QSS dark theme (#0e0e18 bg, #e94560 accent)
Archives	zip (builtin), 7z (py7zr), RAR (rarfile + WinRAR/7-Zip)