From Warhammer 40k - Lexicanum
A new threat is rising...
One that has been sleeping for millions of years...
And it will consume the all in its name...
The Metal Beasts Return
The Ancient Past
The Necrontyr were once the race of flesh and blood people who now reside within the cold, hard shells of the Necrons. They were an amazingly advanced race who mastered the cold art of science in their pursuit of a way to overcome their ravaging sun. They turned their attention to the study of the star and eventually found what later became the C'tan. From the moment the first C'tan appeared from over the Starlight Bridge, their fate was sealed, to become servent warriors in their quest to consume all life in the galaxy.
The forces of the Necrons
The Necrons are a ruthless race with no concern for anything other than destruction. They combine deadly firepower with terrifying close combat power. They also make use of a heavily armed and armoured vehicle known as the Monolith which is made from their living metal and is very difficult to stop. They rely on deadly, rapid attacks, making use of skimmers with heavy weapons and rapid firing weapons to encircle and eradicate the enemy. The move with an implacable force, bringing fright to almost anything that stands in their way.
The C'tan are the race of god like figures ruling over the Necrons. They were originally space faring creatures, as old as the universe itself. They leached off of the stars throughout the galaxy and were eventually discovered by the ancient Necrontyr. They were brought to this realm and placed within their Necrodermis, morphable suits of living metal. Their appetite quickly changed to consuming life, a much more appetising substance. Eventually, they turned the Necrontyr into the Necrons in their quest to consume the galaxy.
The Weapons of Doom
The Necrons are armed with devastating gauss weapons that strip the molecules from the very surface of the skin/armour, killing fairly slowly before moving onto the next target. Because of their nature, even the most basic Necron weapon can penetrate the thickest armour, although it is less likely the thicker the armour. They also use non-gauss weapons that are equally deadly and wielded by the strongest of their forces. These are analysed in the Necron Armoury.