I'm trying to run two ecs worlds on one game instance. I figured that I have to create worlds and then call Update() manually on each system. However now that I'm running everything manually, I also seem to lose the default systems running behind the default World. So systems like TransformSystem and MeshInstanceRendererSystem are not updated. Also systems are not visible on entity debugger window when they are updated manually. Is there a way to call these "essential" systems automatically? Or hook my worlds to update just like the default world? There's World.Active but that's for a single world. Any pointers how this might be best to implement would be appreaciated Right now I can only think of just going through the codebase and try to figure out when each default system should be run. I have a feeling that this is bound to cause weird bugs if I forget to run something essential. Or if I just run things in wrong order. Especially as the codebase and workflow in general is new to me. ---- To give some context I have a multiplayer game that has completely separated client and server logic running on editor. Physics are separate, packets are sent and received from/to the same machine, etc. The point is that I don't have to make a build to run client and server separately which takes ages on HDRP. Separate ECS worlds would keep entities isolated from each other.