This mod expands on the heavy core block from the 1.21 tricky trials update and adds a new armor
set a new sword and new items paired with it to start you will need a heavy core and put it in a blast furnace to smelt
once its smelted you will get a molten core
with said molten core when put into a smithing table with these items
you will ubtain molten items to tuen into the new armor and sword
And too craft the item casts. You craft them like so with there corresponding iron tool
And once you have gotten the molten tool if you right click them on a cauldron with water in it you will get your new item
- Edition: Minecraft Java
- File type: .jar
- Minecraft versions listed: 1.21.4, 1.21.5
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Modrinth — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — How to install Minecraft Java mods & modpacks walks through it step by step.
- Ships as heavy_expansion-1.0.0-neoforge-1.21.4.jar — drop this file into the mods folder
- Download size: 407 KB
- Download link checked 11 Sept 2026 — working
These come from our own check of the pack file, not from the source page.