If a planet has no faction controlled, does building city on it require permission? Is it possible that a sector or system is controlled by a faction but systems or planets inside it has no faction controlled? What about building city under this situation? Thanks.
If a planet is not controlled by a faction, and the planet's surface is accessible (not shielded), anyone can put up a city. A lot of planets not directly controlled by a faction are completely shielded and either a faction is in the process of building up enough population for control, or the planet is 'owned' by an individual and controls it purely via shield or slab bombing, which is covering the whole planet with cities. The only other case is when the planet is a racial homeworld, they are usually owned by darkness or are unable to be built upon.