Necrons - Necron Combat Doctrine: Hibernating deep within the hearts of their Tomb Worlds, the Necrons have been dormant for more than 60 million Terran years.Scattered Necron raiding parties heralded the undying race's awakening to full activity once more in the 41st Millennium, but now as their thirsty Star Gods, the C'tan, rise to a hungry wakefulness for life energy, the dreaded Necrontyr have returned to claim the galaxy for their own.Every Necron Tomb World has been constructed to accord to a complex template that was devised by the Necrontyr at the height of their civilisation. Utilising physical principles and technology that have not been rediscovered by any other intelligent species since they began their long sleep, the Necrons created immense subterranean warehouses to store their race for the millions of Terran years they would spend inactive.Using their mastery of advanced interdimensional geometry, the Necrons built massive chambers that could house tens of thousands of their kind in a space seemingly larger on the inside than without.Deep beneath these pyramidal structures, the Necrons stored their horrific weaponry and erected powerful temporal stabilisers that would shield these warriors and their savage weapons from the ravages of time much like a stasis field.Each Tomb World, once it has been reactivated, awakens its sleepers in a rigid and predictable algorithmic sequence that is as inevitable as the dying of the stars.First, the Tomb World releases swarms of robotic Canoptek Scarab and Canoptek Spyder constructs to attend to the rudimentary needs of the stasis tombs. Soon after the mindless Necron Warriors are reawakened and begin reconnaissance patrols of the region of the world surrounding their tombs.Using the information gained by these Necron Warriors' scouting missions, the Tomb World's automated systems -- its "Tomb Mind" or "Deep Spirit" -- assess the current circumstances that dominate its environment. According to ancient, pre-determined algorithms, the stasis tombs then bring on-line other Necron machineries and weapons as the circumstances warrant.The Necron Overlord or [[[Necron Lord|Lords]] present on the Tomb World are encoded with this information and the data necessary to form artificial personalities so that when they awaken they can embody the singular purpose of the Tomb World and make independent decisions.A large population centre of one of the galaxy's younger races, usually Humanity, may have been settled unwittingly on what is actually a Necron Tomb World. When this situation is encountered, the Tomb World's encoded master programming reacts extremely aggressively to defend its hibernating charges.These Tomb Worlds are the ones that have activated the most rapidly during the current awakening of the Necrons and are now hives of activity for the undying race.As their automated systems delve ever deeper into their existing archives of data and storehouses of units and weapons, the Tomb Worlds whose areas of influence have been "invaded" by the younger races are gearing up to begin what will eventually become a full-scale retaliatory action against the Imperium of Man and any other organised force that stands in the Necrons' way.This is a programmed behaviour pattern that Imperial savants have dubbed "the Harvest." When it comes to pass, it will be a genocidal-level event on a par with the War in Heaven against the Old Ones millions of Terran years ago.