Marine Chapter

A Chapter is a completely autonomous military unit made up of one thousand of the superhuman warriors known as Space Marines or Astartes and their related vehicles, starships and support personnel. Each Chapter serves collectively with the others of its kind as part of the Imperium of Man's Adeptus Astartes. Every Chapter is entirely autonomous from every other Adepta of the Imperium, including the Inquisition, and takes its orders only from the High Lords of Terra themselves.