Vigo sector is a large Imperial sector in Segmentum Tempestus, not very far from the edge of the Imperium, almost surrounded by wilderness space. During the war against Hive Fleet Leviathan, Vigo sector was cut off from reinforcements by order of the Munitorum to allow these forces to be used against the Tyranids; the timing was inopportune, as shortly after that, the sector was invaded by the forces of Chaos, and several Ork Waaaghs.