Before a co-op session, agree whose World is the campaign home.
Solo or 1–8 players
Dimraeth supports solo play and online co-op for up to eight players. The public FAQ describes a peer-to-peer host model rather than dedicated servers.
Character progress travels
Your character, attributes, equipment and personal progression are the portable layer. This is the layer you should prepare before joining another player's world.
World progress stays with the World
Story Progress, Buildings and Recruited Allies are tied to the host's World. Treat a friend's save as its own progression track rather than assuming it advances yours.
Choose a host deliberately
For a shared campaign, let the player who wants to own the settlement and story route host the World. Everyone else can bring their character into that world.
Troubleshoot loot and building access
Current community reports call out three settings worth testing independently: personal loot controls which character sees most drops, LockBuildtoOwner limits access to objects such as chests and doors to the builder, and a chest's Public / Private state affects whether its materials remain available to Crafting Benches. These observations still need reproduction on the current client.
Confirm difficulty before building
The current post-launch discussion says World difficulty is selected at creation and cannot be changed later. Create the World, exit and re-enter once to confirm difficulty, public status and host settings. If it is wrong, back up the save and consider rebuilding before investing NPCs, buildings or story progress.
Move a World without losing the original
On Windows, the reported save folder is %USERPROFILE%/AppData/LocalLow/Mudtek/Dimraeth/Worlds/. Copy <world_name>.jrwf together with <world_name>.jrwf.bak1 and .bak2. Rename or back up a same-name destination file because the copy can overwrite it; third-party sync is optional, not a prerequisite. Character progress travels with the character; Story Progress, Buildings and recruited NPCs need the World file.