There are seven main worlds in this universe. They live alongside each other, but some are aware of the existence of others.
This speaks for itself. The world we live in now.
A shadowy place, from which came the Dark Master.
This is where all the members of StarGate Inc. reside.
Yes, this is a world. Everything here is part of Ender's memories, thoughts and feelings.
Only a select few are allowed to enter this realm. Time does not exist in this zone.
These are special. They include:
And many more besides.