Factions are exclusive to Galaxy Awaits: Rise of an Empire as part of the game structure. Players must choose from one of four Factions for their character to assist in forming In-Game alliances and enemies, and facilitates the game story and economy. 

Factions also have an entry in the Rules describing the game mechanics. 

THE FOUR FACTIONS

Empire - The militaristic, oppressive government of the galaxy.

Independent - A catch-all for characters, peoples, and organizations not affiliated with the other Factions.

Rebellion - A loose band of cells working to free the galaxy from the rule of the Empire.

Selvarin - The local residents of the planet Selvaris, where the game story takes place.