Old Ones (Warhammer 40,000)

The Old Ones are a mythical and mysterious race or possibly a group of distinct species in the table-top wargame Warhammer 40,000. They played a pivotal role in the history of many races, including the Eldar, Jokaero, Humans, Orks and Necrons.

History
The Old Ones of Warhammer 40,000 history are possibly an ancient species of nearly immortal, cold-blooded beings, who were probably the first race in the galaxy to have evolved sentience (however, the C'tan predate the Old Ones, but the C'tan didn't partake in the affairs of the Galaxy until the Necrontyr gave them physical bodies just before the War in Heaven). A supposedly benevolent and gentle race, they appear to have wished to nurture the younger races and protect them from the C'tan. The Old Ones were inherently patient as a race, and before attempting to explore the galaxy they made an extensive study of astronomy, which led them to discover the Immaterium. At the time, the Immaterium was as yet unaffected by the psychic emissions of other intelligent races, and so it was a calm and steady realm. The Old Ones were able to exploit the Immaterium, allowing them to travel across the galaxy at a whim without the need of starships.

In their travels, the Old Ones seeded many worlds with life, and encouraged the development of indigenous animal and intelligent life on many more. Life on Earth is believed to have been created in this way as the Old Ones probably first seeded it with primitive, single-celled lifeforms.

Encountering The Necrontyr
One of the few races the Old Ones encountered that were already sentient without their intervention were the Necrontyr. Where the Old Ones were long-lived, with an average lifespan lasting for many Terran millennia, and had access to technology that allowed them to travel from settled world to world instantaneously through a network of Warpgates called the Webway, the Necrontyr were short-lived, and were bound to but one world. The Necrontyr grew increasingly jealous of the Old Ones, and eventually set about going to war with them to wipe them out and claim their technology. The Old Ones easily outmaneuvered these early, clumsy Necrontyr strikes by making use of their Webway, and the Necrontyr were soon defeated.

However, the Necrontyr then discovered that a C'tan, a member of a race of enigmatic energy beings who had come into existence not long after the act of Creation itself, was living within their home star, feeding on the sun's radiant power. In a short time, the Necrontyr managed to create a technology based on "living metal" or Necrodermis, that allowed the C'tan to manifest itself physically by enclosing itself within a construct made from Necrodermis. The Necrontyr soon began to view their C'tan and its fellows as gods. With the help of the C'tan, the Necrontyr were able to turn the tide of their war against the Old Ones, largely by transferring their own consciousness into robotic bodies forged of Necrodermis like their C'tan "Star Gods." Unfortunately, the process of conversion dampened the Necrontyr's emotions and intellects, turning them into little more than mindless, eternally anguished slaves for the C'tan, who discovered that feeding on the life energies of other intelligent beings was far more "tasty" than the bland energy given off by stars. After their transformation, the Necrontyr became known as the Necrons and began cleansing the worlds held by the Old Ones and their allied species, feeding whole planetary populations to the foul appetites of their C'tan masters.

In the conflict that followed, called the War In Heaven by the Eldar's lorekeepers, the Old Ones created and modified many new races to help them combat the Necrontyr. The C'tan had no ability to comprehend or manipulate the Immaterium, and thus the Old Ones came to the conclusion that they would create a series of races attuned to the Immaterium, in order to use the vast repository of energy present there against the C'tan. Of these races, a few survive today, such as the Eldar, Jokaero, Hrud, the Krork (who, it is speculated, eventually devolved or mutated into the Orks and other Greenskins) and to a certain extent Humans.

The Enslavers
The new psychically-attuned races' darker impulses had a devastating effect upon the Immaterium: their emotional emissions bled into it, twisting the once peaceful dimension into a violent realm, fueled by their strongest (and usually darkest) emotions, giving the Immaterium a new name, the Warp. The vast majority of the sentient beings that dwelled in the Immaterium, known as Daemons to the Imperium of Man, became malicious and dangerous, earning their daemonic moniker.

One such Daemonic race, called the Enslavers, managed to discover a way to force entry into the material realm, and began to psychically enslave huge numbers of sentient beings. This new invasion dealt a fatal blow to the Old Ones (all of whom were killed or fled) and forced the C'tan and their Necron minions into hibernation on the Necron's so-called "tomb worlds" across the galaxy some 60 million years ago, as the C'tan (who fed on the energy produced by the sentience of other beings) had their food supplies stolen from them. It is hinted in recent publications that some of the Old Ones did indeed survive the War In Heaven.

Slann
In the fictional universe of Warhammer 40,000, the Slann were a reptilian or amphibian species who were servants of the Old Ones (although some sources state that they in fact are the Old Ones) not unlike the Lizardmen of Warhammer Fantasy. The Slann are reputed to have created some of the major races in the Warhammer 40,000 universe, the most notable of which are the Orks (who are hinted to be referring to them as the Brainboyz, though the most recent publication of the Ork codex has implied that the snotling fulfilled this role) and Eldar (who are the only race that keeps records from the age) who were created with their psychic abilities to take part in the war between the Necrons and the Old Ones in which they were all but wiped out by the C'tan and the Enslaver plague. The Human race was a race for which basic evolution was allowed to continue without the guidance of the Old Ones.

There were five generations of Slann spawned by the Old Ones. The Slann of the first generation have all died off, many likely killed in the war between the Old Ones and the Necrontyr. This is very similar to the story of the Slann race in Warhammer Fantasy, if not the same storyline.

Slann ruins and relics occasionally feature in novels or short stories set in the Warhammer 40,000 universe.