Online co-op, not a shared MMO world
A group can have eight players including the host, with drop-in and drop-out play. The official FAQ describes peer-to-peer hosting and rules out dedicated servers and local split-screen. Plan for an online session in someone's world rather than a permanent public realm.
What follows your character?
The developer says your level, equipment, inventory, spells and personal progression travel between worlds. This makes the character and the world different units of progress. Do not interpret arriving in another world as proof that all of its campaign state has been copied to your own.
What stays with the world?
Story progress, recruited allies and buildings belong to each world. Our recommendation for a continuing group is to agree on one campaign world before investing time together. If you switch worlds later, distinguish the hero you brought from the story and settlement you are returning to.
For example, helping with a building in a friend's world does not make that building part of every other world you visit. This is a consequence of the stated save boundary, not a separate claim about construction permissions or material refunds.
Agree on a session plan before joining
Choose the campaign world, who will host, and a shared goal such as exploration or building. At the end, note which world contains the progress you want to continue. This small organizational step is more useful than assuming every player has received identical world changes.
The verified sources do not establish an exact invitation-menu sequence, reconnect recovery procedure or numerical enemy-scaling formula. Those details are not part of this guide; if a session fails, record the game version, host and guest roles, and what happened instead of treating a guessed workaround as guaranteed.
Can you play without a group?
Yes. Solo play is supported, so a full party is not a prerequisite. Coverage checked September 16, 2026; the hosting and save distinctions above are the important planning constraints, not a promise about connection quality or future server features.