A faction is a collective of influential people or entire organizations united behind some specific goal, often one that is mutually exclusive to everyone else's. The forces that have shaped the past, that shape the present and that will shape the future are identified as factions. Sometimes these are quite formal organizations with clear membership and heirarchy, as in the case of the Imperial Government; other factions are totally decentralized, and united only by an unconscious and even accidental shared interest, as in the case of the Undead.