Playing alone
Jagex states that you can play offline solo. You do not need to join a public world just to experience Ashenfall and the Kuldra Saga. The core loop—gathering, crafting, building and questing—also works as a solo adventure. If you want to start without coordinating friends, create your world and follow the official tutorial at your own pace.
Ordinary co-op worlds
The September 2026 news release describes a player plus up to three friends, meaning four players in an ordinary co-op team. The 1.0 release added crossplay and invite codes for finding and joining worlds. A host can choose whether a multiplayer world is crossplay-enabled when loading it. See Join a World for the code entry and Crossplay & Cross-Save for the platform distinction.
Dedicated servers are a different option
Jagex’s March 2026 dedicated-server guide documented support for up to six players as of version 0.11. That is a published server-specific figure, not a replacement for the four-player ordinary co-op description. Capacity and server behavior should be checked against the current official guide and the version running on the server.
The dedicated path requires renting or running a server, configuring it and keeping its game version aligned with players’ clients. For a small group just starting the game, an ordinary hosted co-op world has fewer setup steps. If you need a persistent server or the documented larger capacity, read Dedicated Servers.