The C'tan are a species of godlike beings and the leaders of the Necrons.
The C'tan were originally a race beings that fed on the energy of stars. This changed when they encountered the Necrontyr during their war with the Old Ones. The Necrontyr created physical bodies made of necrodermis to communicate with them. This led to the C'tan developing a taste for the energy of living beings over the "tasteless" energy of stars. The C'tan offered the Necrontyr a chance to win their war against the Old Ones by converting their minds to bodies made of necrodermis. The Necrontyr accepted and became the Necrons, coming to worship the C'tan as gods. The two races then proceeded to wipe out the Old Ones. The Old Ones, however, genetically engineered a race of their own, the Eldar, to fight the C'tan and the Necrons. The Eldar created weapons specifically to kill the C'tan that came to be known as the Blackstone Fortresses.
Ultimately, not even the Blackstone Fortresses could defeat the C'tan, but the Eldar managed to stop them by tricking them into feeding off the energy of each other. Only four of the C'tan survived the cannibalism spree; they went into hibernation. So far, two of them, the Deceiver and the Nightbringer, have awakened and will personally aid their Necron servants in battle.
There are rumors that at least some members of the Adeptus Mechanicus worship the C'tan known as the Void Dragon.
- Void Dragon: The Void Dragon is arguably the most powerful of the C'tan, having once destroyed 6 Blackstone Fortresses in a single battle during the war against the Eldar. The nature of its powers are unknown, although it is implied they relate to machinery. It is also implied to have been defeated by the Emperor of Man in the past and that it is in fact the Machine God worshipped by the Adeptus Mechanicus.
- Nightbringer: Resembling the Grim Reaper and wielding a scythe, he is the most violent of the C'tan, having wiped out entire regions of space in his hunger (or for fun). His slaughter literally put the fear of death into the young races. He was accidentally released by the Dark Eldar.
- Deceiver: He possesses less outright power than other C'tan, but compensates for it with his power to influence the thoughts of others and shapeshift. He was the C'tan that led the Necrontyr to become the Necrons.
- Outsider: Very little is known about him, other then he has similar traits to the Nightbringer and was driven insane by the Eldar Laughing God, causing him to leave the galaxy.