[Astromancer]

In GURPS: Teradyne, there were hints that there was a secret fleet being built out in deep space to attack the Earth and force the Earth to grant the Teradyne corporation sovereignty over all of the solar system beyond Earth. A hidden off Earth realm could be trying (either seriously as a real threat or stupidly as a real problem, or with total incompetence as a real laugh) to build a space fleet. And an Earthside Hidden Realm could be hiding out because they fear someone is building an Earth Conquest fleet.

However you slice it, real or silly, friend or foe, it leads to lots of conflicts. And conflicts lead to stories.