The Necrons are a mysterious xenos species of humanoid, robotic skeletal warriors that have lain dormant in their stasis-tombs for more than 60 million Terran years, though they have begun to awaken at last. They are the soulless creations and former servants of the ancient C'tan, the terrible Star Gods of Aeldari myth.
The Necrons are ancient beyond reckoning, predating even the birth of the Aeldari. At long last, however, they are beginning to awaken from their Tomb Worlds, for the galaxy is ripe for conquest and the restoration of the Necron Empire since the disappearance of the Old Ones more than 60 million standard years ago.
"Every machine and engine is made up of many constituent parts, all of which are necessary for it to function.
Sometimes, however, components break, or cease to work optimally.
When that happens, the weak element must be excised and replaced.
All are expendable if necessary, for the function of the whole."
A Tomb World is one of the worlds across the Milky Way Galaxy where the ancient and terrible xenos known as the Necrons chose to go into hibernation over 60 million standard years ago, deep beneath its surface in their specially prepared catacombs and tombs.
Many Tomb Worlds are now settled planets of the Imperium of Man and their status as a Necron Tomb World remains unknown until the Necrons beneath its surface begin to awaken, much to the detriment of all life on the world. An unknown number of these planets exist across the galaxy in the 41st Millennium.