MJOLNIR Core

Description

MJOLNIR Core Launcher is a free, open-source mod manager for Halo Campaign Evolved. It finds your game, installs the modding runtime and the MJOLNIR mod pack for you, and lets you turn mods on and off without ever touching a config file.

Modding HCE normally means manually installing UE4SS as a

dwmapi.dllproxy, dropping signature overrides into the right folder, hand-editing

mods.txt, and hoping you put everything in the correct directory. The launcher does all of that in one click, verifies every installed file against a SHA-256 manifest, and gives you a single switch to go back to a clean, unmodded game whenever you want — which matters if you ever want to play vanilla or verify a bug isn't caused by mods.

It's part of MJOLNIR Core, an open-source modding framework and community platform for HCE. The launcher is MIT-licensed and the full source is on GitHub.

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Installation instructions

• []Download the

  MJOLNIR-Launcherinstaller from the Files tab.[/]

  [](Optional but recommended) Verify the download. Compare the SHA-256 hash against the checksum published on the official download page at mjolnircore.com/download:

  (Get-FileHash .\MJOLNIR-Launcher.msi -Algorithm SHA256). Hash[/]

  []Run the installer. Windows SmartScreen may warn about an unrecognised publisher — click More info → Run anyway. On Windows 10 you may also be prompted to install the Microsoft WebView2 runtime; it's already present on Windows 11.[/]

  []Open MJOLNIR Launcher. It automatically detects your Halo Campaign Evolved install (Steam libraries on any drive, or Xbox Game Pass). If detection fails, point it at your game executable under Settings.[/]

  []Click "Install Modpack." The launcher downloads the UE4SS runtime and the MJOLNIR mods, extracts them into

  Meteorite\Binaries\Win64\, and verifies every file's checksum. Progress is shown live.[/]

  []Pick your launch method in Settings — Steam, Xbox Game Pass, or a direct path to the game EXE.[/]

  []Hit Launch. Mods load during game startup, so restart the game after enabling or disabling anything.[/]

Uninstalling: use the Uninstall Modpack button in the launcher to cleanly remove UE4SS and all mods from your game folder, then uninstall the launcher normally from Windows Settings. Nothing is left behind in your game directory.

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Main features

• []Automatic game detection — finds Halo Campaign Evolved across Steam libraries on any drive (including custom library folders read from

  libraryfolders.vdf) and Xbox Game Pass / Microsoft Store installs.[/]

  []One-click modpack install — downloads and installs the UE4SS runtime, the MJOLNIR mods, engine signature overrides, and the tuned config, all into the correct locations. No manual file copying.[/]

  []SHA-256 integrity verification — every installed file is checked against a signed manifest during install, and you can re-verify at any time to catch a corrupted or tampered install.[/]

  []One-switch vanilla toggle — disable the entire modpack instantly without uninstalling anything, so you can jump back to a clean game and re-enable mods later with one click.[/]

  []Per-mod toggles — enable or disable individual mods from a list that shows each mod's name, version, and description, pulled live from your install. No editing

  mods.txtby hand.[/]

  []Launch from anywhere — start the game through Steam, Xbox Game Pass, or a direct executable path of your choosing.[/]

  []Built-in auto-updater — the launcher checks for new versions on startup and installs cryptographically signed updates in place.[/]

  []Clean uninstall — removes the proxy DLL, the UE4SS folder, and all mod files in one action.[/]

Mods included in the pack:

What it does

MJOLNIR FlyCam

Free-flying debug camera —

F8toggle, WASD movement, mouse look (

F9), HUD toggle (

F7), shift to boost,

]to change speed

MJOLNIR Console Enabler

Unlocks the Unreal developer console in the shipping build (

MJOLNIR Core

Framework runtime and shared helper l