Marie's Wonderland

An attempt at a private server implementation for the mobile game NieR Reincarnation.

Game information

• Built in Unity 2019.4.29 with C# and IL2CPP
• Has a gRPC-based API server
• Has a supplementary web-based HTTP API

Current status: We can get past the initial loading screens and reach the in-game state, but the game is not fully playable, yet.

Requirements

PC

• .NET 10 SDK
• Visual Studio 2026 or Rider
• Android Platform Tools (adb)

Phone

• An Android device or an Android Studio emulator (physical device not required)

Patching (Google Colab)

• A Google account to run the patcher notebook

Setup overview

1. Run the server

Open MariesWonderland.sln and run the project, or from the src/ directory

The server listens on the standard HTTP and HTTPS ports on localhost:

• http://localhost (port 80) - used for HTTP asset serving
• https://localhost (port 443) - used for gRPC (HTTP/2)

2. Expose the server

The game communicates over gRPC (HTTP/2). You do not need ngrok or an external tunnel if your emulator or device can reach your machine directly.

• If running on an emulator: configure the emulator to reach the host (Android Studio emulators usually can reach the host).
• If running from a remote device or across a network: open ports 80 and 443 on your firewall/NAT and ensure those ports are forwarded to the machine running the server so the game can reach http(s)://<your-host>.

Ensure any network path supports HTTP/2 for gRPC traffic on port 443.

3. Patch the APK

The scripts/patcher.ipynb notebook runs entirely in Google Colab - no local toolchain needed.

1. Open Google Colab and upload scripts/patcher.ipynb
2. Fill in the configuration at the top of the code cell:
   • protocol - http for plain tunnels, https for TLS-terminated endpoints
   • server_host - your hostname (without protocol), e.g. 192.168.1.1
   • server_port - leave empty unless using a non-standard port
3. Run the single code cell
4. Wait for it to complete and the patched APK will be automatically downloaded

What the patcher does:

• Rewrites server URLs and hostnames in global-metadata.dat (IL2CPP string literals)
• Applies ARM64 binary patches to libil2cpp.so: SSL bypass, encryption passthrough, plain Octo asset list
• When using http: patches AndroidManifest.xml and network_security_config.xml to allow cleartext traffic

Note: Replacement strings must not be longer than the originals. Use short hostnames and omit the port if you run into length issues.

4. Install and run

Install NieRReincarnation-patched.apk in your phone or emulator. Launch the game. It will connect to your local server.

Configuration

Server settings live in src/appsettings.development.json:

{
  "Server": {
    "Paths": {
      "AssetDatabase": "<path to extracted asset revisions>",
      "MasterDatabase": "<path to extracted master data>",
      "ResourcesBaseUrl": "http://<your-host>/aaaaaaaaaaaaaaaaaaaaaaaa"
    },
    "Data": {
      "LatestMasterDataVersion": "20240404193219",
      "UserDataPath": "Data/UserData",
      "MasterDataPath": "Data/MasterData"
    }
  }
}

• The ResourcesBaseUrl value must be exactly 43 characters long.
• If you change the length of that segment, you may also need to update the server-side minimal API that serves the short path (the /aaaaaaaa... handler) so its expected length matches your new value.

Project structure

src/                  .NET 10 gRPC + HTTP server
  proto/              protobuf service definitions
  Services/           gRPC service implementations
  Data/               in-memory data stores (master + user)
  Models/             entity and type definitions
  Extensions/         DI, HTTP, and gRPC helpers
  Configuration/      strongly-typed options
  Http/               HTTP API handlers (asset serving, etc.)
scripts/
  patcher.ipynb       Google Colab APK patcher notebook
  hooks.js            legacy Frida hooks (for reference only)

Disclaimer

See DISCLAIMER.md.

Special Thanks

• onepiecefreak3
• Walter-Sparrow