Download MJOLNIR Launcher
One-click mod management for Halo Campaign Evolved. Auto-detects your game, installs mods, and launches via Steam.
Windows Installer (.msi)
Requires Windows 10/11 (64-bit) and WebView2 runtime
Verify Your Download
Always verify the SHA-256 checksum to ensure your download hasn't been tampered with.
Official Build Checksums (Latest Release)
Compute the hash of your downloaded file
(Get-FileHash .\MJOLNIR-Launcher*.msi -Algorithm SHA256).Hashcertutil -hashfile MJOLNIR-Launcher.msi SHA256Compare the hashes
If the hash you computed exactly matches the one in checksums.txt, your download is authentic and unmodified.
The tools install from here too
The launcher's Tools view installs and updates the MJOLNIR Tag Editor — the Guerilla-style editor for the game's tags, textures, audio and scripts — and checks every build against its published hash.
See the toolsPrefer a command line?
mjolnir reads and edits the same tag data from a terminal — list a group, print a tag's decoded fields, change one, and bake the result into a container the game loads. It runs on Windows, Linux and macOS, with a checksum published for every build.
# Windows
scoop bucket add mjolnir https://github.com/devnull9090/mjolnir-core
scoop install mjolnir
# macOS and Linux
brew tap devnull9090/core https://github.com/devnull9090/mjolnir-core
brew install mjolnirAlso as .deb and .rpm, or a plain archive. The Linux build is statically linked, so it runs on any distribution.