An all-in-one desktop tool for managing Seamless Co-op mods across multiple FromSoftware games. Install mods, configure settings, manage save files, launch co-op sessions, and create desktop shortcuts — all from a clean web-based dashboard running locally on your PC.
Note: This is a manager tool only. The Seamless Co-op mods themselves are created by LukeYui. All credit for the actual mods goes to them — this project simply provides a convenient way to install, configure, and launch them.
Quick install: Download
Setup_FromSoft_Coop_Manager.batfrom the latest Release, double-click it, and you're done.
| Dashboard | Settings |
|---|---|
 |
 |
| Save Manager | Mod Installer |
|---|---|
 |
 |
| Game | Co-op Mod | Nexus Mods |
|---|---|---|
| Armored Core 6: Fires of Rubicon | AC6 Seamless Co-op | Link |
| Dark Souls Remastered | DSR Seamless Co-op | Link |
| Dark Souls III | DS3 Seamless Co-op | Link |
| Elden Ring | Elden Ring Seamless Co-op | Link |
| Elden Ring Nightreign | ER Nightreign Seamless Co-op | Link |
The tool automatically scans all your Steam library folders across all drives and detects which games you have installed. It uses Steam's
appmanifestfiles to verify a game is truly installed (not just leftover files from an uninstall).
- Shows all detected games as cards with Steam cover art
- Each card displays the mod installation status (installed / not installed)
- Three actions per game:
- Launch Co-op — starts the co-op mod launcher directly
- Manage — opens the game's detail view with all sub-tabs
- Desktop Shortcut — creates a Windows desktop shortcut for the game's co-op launcher, using the game's Steam cover art as the icon and named clearly (e.g., "Dark Souls III Co-op")
- Displays the game's full Steam library cover art
- Double-click the cover art to launch the co-op mod
- Visual feedback during launch (launching → launched states)
- Warning shown if the launcher executable is missing
- Reads and displays all settings from the mod's
.iniconfig file - Automatically determines input types from the mod's own comments:
- Dropdowns for settings with limited choices (0/1, on/off)
- Number fields with min/max ranges
- Text inputs for passwords and open values
- Shows the setting description (pulled from INI comments)
- Dirty tracking — changed fields are highlighted with a change indicator
- Save confirmation — shows a table of all changes before saving
- Undo button — reverts all unsaved changes
- Reset to Defaults — restores every setting to the mod author's default values
- Unsaved changes protection — prompts before switching tabs or closing the browser
- Changes are saved directly to the mod's config file on disk
- Lists all save files in the game's
%APPDATA%save directory - Shows base game saves (
.sl2) and co-op saves (.co2) side by side - Transfer — copies a base save to a co-op save (or vice versa), with a timestamp to prove freshness
- Backup — creates timestamped backups of individual save files
- Restore — restores any backup with a confirmation dialog
- Delete — removes backups with confirmation
⚠️ Ban Risk Warning: Transferring co-op saves back to the base game (Co-op → Base Game) and then playing on official FromSoftware online servers may result in your account being flagged or banned. Co-op mod saves can contain data that the anti-cheat system considers illegitimate. Use this feature at your own risk. The authors of this tool are not responsible for any bans or penalties incurred.
- Direct link to the mod's Nexus Mods page for downloading
- Automatically scans your Downloads folder for matching mod zip files
- One-click Install — extracts the zip into the correct game directory
- Delete button next to each zip — removes the download with confirmation to keep your Downloads folder clean
- Post-install cleanup prompt — after a successful install, asks if you'd like to delete the zip file
- After installation, hidden tabs (Launch, Settings, Saves) are revealed automatically
- Refresh button to re-scan Downloads
- Windows 10/11
- Steam with at least one supported game installed
That's it. The installer handles everything else — Python, dependencies, shortcuts — all automatically.
- Download
Setup_FromSoft_Coop_Manager.batfrom the latest GitHub Release - Double-click it
- Done.
The single installer file does everything:
| Step | What it does |
|---|---|
| 1/6 | Installs Python automatically if missing (via winget or direct download) |
| 2/6 | Downloads the full application from GitHub |
| 3/6 | Installs to %LOCALAPPDATA%\FromSoftCoopManager |
| 4/6 | Creates an isolated virtual environment |
| 5/6 | Installs dependencies (Flask, Pillow) |
| 6/6 | Creates launcher scripts and a desktop shortcut |
If you prefer to clone the repo (e.g., for development):
git clone https://github.com/spikehockey75/FromSoftSeamlessCoOpManager.git
cd FromSoftSeamlessCoOpManager
Setup_FromSoft_Coop_Manager.bat
The installer detects it's already inside the repo and skips the download step.
After installation, start the app any of these ways:
| Method | How |
|---|---|
| Desktop shortcut | Double-click "FromSoft Seamless Co-op Manager" on your Desktop |
| run.bat | Double-click run.bat in the install folder |
| From installer | The installer asks "Launch the app now?" at the end |
Your default web browser opens automatically to http://127.0.0.1:5000.
No console window! The desktop shortcut and installer both use a silent launcher — the server runs entirely in the background with no terminal window. Just close the browser tab when you're done.
- The app opens in your browser showing a welcome screen
- Click 🔍 Scan for Games in the top-right corner
- The tool scans all drives for Steam libraries and co-op mods
- Game cards appear on the dashboard for each detected game
Click Manage on any game card to access its sub-tabs:
- Launch — launch the co-op mod directly
- Settings — view and edit all mod configuration
- Saves — manage save files and backups
- Mod Installer — install or update the mod from a downloaded zip
Click ← All Games to return to the dashboard (data is always refreshed).
- Click Manage on the game card
- Go to the Mod Installer tab
- Click the Nexus Mods link to download the mod zip
- The tool automatically detects the zip in your Downloads folder
- Click Install — confirms and extracts into the game directory
- After install, you're prompted to clean up (delete) the zip from Downloads
- The Launch, Settings, and Saves tabs become available
- App shortcut — created automatically by
Setup_FromSoft_Coop_Manager.bat→ "FromSoft Seamless Co-op Manager" - Game shortcuts — click Desktop Shortcut on any game card → creates e.g., "Armored Core 6 Co-op" with the game's Steam cover art as the icon, pointing directly to the co-op launcher
If you install or uninstall a game, click Scan for Games again. The tool verifies Steam app manifests, so uninstalled games are automatically removed even if leftover mod files remain.
FromSoftSeamlessCoOpManager/
├── Setup_FromSoft_Coop_Manager.bat ← One-time setup (double-click first)
├── Uninstall_FromSoft_Coop_Manager.bat ← Uninstaller (removes app + shortcuts)
├── launch.vbs ← Silent launcher (no console window)
├── run.bat ← Starts the app (called by launch.vbs)
├── server.py ← Flask backend (scanner, APIs, launcher)
├── requirements.txt ← Dependencies (flask, Pillow)
├── config.json ← Auto-generated after first scan
├── FSSIcon.png ← App icon source (PNG)
├── FSSIcon.ico ← App icon (auto-converted by installer)
├── README.md ← This file
├── .venv/ ← Python virtual environment (auto-created)
├── icons/ ← Cached game icons for desktop shortcuts
├── templates/
│ └── index.html ← HTML template
└── static/
├── style.css ← Dark-themed UI styling
└── app.js ← Frontend logic (dashboard, tabs, forms)
No. The co-op mod prevents you from connecting to FromSoftware's matchmaking servers and uses save files different to the non-modded game. There is no way to get banned using this mod unless you modify it with the intent of connecting to vanilla players.
Because the mod introduces new items not found in the base game, it uses a different save file to the normal .sl2 extension. This means you cannot access your Seamless Co-op save files in the base game, and vice versa. Do not revert mod save files back to vanilla save files, as you will likely get banned.
⚠️ The Co-op → Base Game transfer in the Save Manager exists for convenience, but using it and then going online on official FromSoftware servers risks a ban. See the Save Manager section for the full warning.
The automatic Python installation may have failed, or PATH wasn't updated.
Fix: Open a new Command Prompt and run Setup_FromSoft_Coop_Manager.bat again. If it still fails, install Python manually from python.org/downloads and check "Add python.exe to PATH" during install.
Make sure:
- The game is installed via Steam (the tool checks for Steam app manifests)
- If you want Settings/Saves/Launch, the co-op mod must be installed in the game folder
- Expected mod config locations:
- AC6:
<game>\Game\AC6Coop\ac6_coop_settings.ini - DS3:
<game>\Game\SeamlessCoop\ds3sc_settings.ini - Elden Ring:
<game>\Game\SeamlessCoop\ersc_settings.ini
- AC6:
Click Scan for Games or just refresh the page. The app checks Steam's appmanifest_<appid>.acf file — if it's gone, the game is automatically removed from the dashboard.
The server runs in the background — there's no console window to close. To stop it:
- Easiest: Just close your browser tab. The server uses minimal resources and will be cleaned up when you shut down or log off.
- Manual: Open Task Manager (
Ctrl+Shift+Esc), findpythonw.exeorpython.exe, and end the task.
Yes. The app is installed to %LOCALAPPDATA%\FromSoftCoopManager by default. You can move this folder wherever you want, then run Setup_FromSoft_Coop_Manager.bat again to update the desktop shortcut.
No. It only reads and writes the co-op mod's .ini settings file — the same file you could edit in Notepad. It never touches game executables or Steam files. Save file operations only affect save files in %APPDATA%.
This sometimes happens with Python scripts and PowerShell shortcut creation. The app is fully open source — every line of code is readable. To fix:
- Allow the app through your antivirus settings
- Or right-click
run.bat→ Properties → check Unblock → OK
Yes. Add a new entry to the GAME_DEFINITIONS dictionary in server.py. Each entry defines the Steam folder name, config file path, launcher path, save directory, Nexus Mods URL, and default settings. See the existing AC6/DS3/ER entries for the format.
Double-click Uninstall_FromSoft_Coop_Manager.bat in the app folder. It will:
- Stop any running instances
- Delete the app folder (
%LOCALAPPDATA%\FromSoftCoopManager) - Remove all shortcuts (Desktop and OneDrive)
- Clean up all app data
- Delete the install folder:
%LOCALAPPDATA%\FromSoftCoopManager - Delete any desktop shortcuts:
- "FromSoft Seamless Co-op Manager"
- "[Game Name] Co-op" shortcuts (e.g., "Dark Souls III Co-op")
Note: Python (if installed) is not removed automatically. To remove it manually, go to Settings → Apps → Python and uninstall.
That's it. Nothing else is installed system-wide. The virtual environment and all app data are inside the install folder.
| Component | Details |
|---|---|
| Backend | Python 3 + Flask, runs on 127.0.0.1:5000 |
| Frontend | Vanilla HTML/CSS/JS — no build tools, no npm, no frameworks |
| INI Parser | Custom parser that reads mod comment metadata to infer control types (dropdowns, ranges, booleans) and extract default values |
| Game Scanner | Enumerates all Windows drives → finds Steam's libraryfolders.vdf → resolves library paths → checks for known game folders → verifies appmanifest_<id>.acf |
| Icon Generation | Downloads Steam CDN cover art → center-crops to square → converts to multi-size .ico via Pillow |
| Silent Launch | launch.vbs runs run.bat with a hidden window via WScript.Shell; run.bat uses pythonw (windowless Python) when available |
| Shortcut Creation | PowerShell WScript.Shell COM object with [Environment]::GetFolderPath('Desktop') for OneDrive compatibility |
| Save Detection | Scans %APPDATA% for game save folders, matches numeric/hex Steam IDs |
| Dependencies | Flask (web framework), Pillow (image processing) — both installed in .venv |
| No external services | Everything runs locally. Steam CDN is only contacted for cover art images |