The Aether

The aether, known more commonly as the warp, is a metaphysical realm that contains the psychic energy of every living soul in the known universe. Its origins are unknown, but it is believed to have been present since the first inception of the universe. It is an alternate dimension to a realm of chaos, where the laws of reality do not apply to the utter madness found in the warp. There is some confusion regarding the naming conventions of the aether, so most Imperial scribes have chosen to refer the collective force of the aether and the warp as the 'Immaterium '

The warp relays once used the energy found within the warp to transport ships through unquantifiable distances, but since its disuse, the Imperium has been able to reverse engineer the technology found in the warp relays onto its own ships. However, unlike the warp relays, these warp drives do not possess the same degree of 'warp integrity' as the relays. As such, interstellar travel is highly unpredictable and could often incur some losses.

Warp Travel
After the Great Collapse, interstellar activity ceased momentarily due to the galaxy's heavy reliance on warp relays. No one knows exactly why the warp relays failed, but regardless, after the failure of the warp relays, the civilisations of the milky way galaxy have found a number of ways to maneuver the loss of the warp relays. In order to traverse through the warp, a ship must tear the very fabrics of reality itself and enter a realm of madness—where the laws of physics, as they are understood in realspace, do not apply; where the souls who enter the warp are subject to the unsatiated hunger of ever-thirsting gods. The Imperium utilises a crude version of the technologies found on the warp relays, which allows them to cross vast distances at the expense of their livelihoods.

Psychic Uses
"'The aether is what gives a psyker its power. It surrounds us, penetrates us. It binds the galaxy together' — Grandmaester Anakin"The aether is the ubiquitous and metaphysical force that grants a psyker its powers. The technicalities of the aether are not entirely understood, but various organisations across the galaxy have dedicated their Orders in the pursuit of knowledge concerning the aether. One such organisation is the Cardassian Order, one of the oldest Orders in the galaxy—not even its most eldest members know the true extent of its history as the maesters of the order only begun to record their history after its integration with the Old Republic in M1 A.D.

As mentioned, the aether is part of a greater reality known as the Immaterium, where malevolent beings lurk in the vast emptiness of the warp. However, it is from this reality that some individuals gain their strange abilities. Scholars are unsure as to how one is born a psyker; but whatever the phenomenon, these people are capable of bending all known laws of physics. These psykers can cast powerful spells that can alter entire landscapes or call forth the creatures of the warp to aid them, but such spells are often frowned upon by the various orders in the galaxy.

However, due to the nature of the Immaterium, some psykers are very unstable—both with their psychic strength and mental health. The greater their psychic strength, the more likely it is for their mental health to deteriorate faster than a person can blink. Nevertheless, the various Orders of the galaxy have made it their duty to help these individuals hone their psychic abilities, though at the cost of their potent psychic energy. Ever since the creation of the Orders, there have been countless debates regarding the morality of the aether. In the past, psykers roamed freely across the stars, wrecking chaos wherever they appear. Some are able to co-exist with their fellow nonpsykers, while others were corrupted by the enigmatic forces of the warp. Is the aether evil? Maybe, maybe not; for the aether does not fall into the regular definitions of morality. It is the collective emotional energy of all living souls in the materium. Happiness, grief, anger, sadness are all concepts that are deeply ingrained in the aether, so much so that it can create warp phenomenons, like warpspawns or warp storms. The Orders were created to understand the secrets of the aether—to teach its followers that the aether calls for one to be one with the Immaterium. The aether is good, the aether is evil—it is a matter of perspective, but for a psyker, they possess the choice to define themselves based on their usage of the aether. Does one want to aid those in need or do they wish to be tainted by its seductive powers.

Daemonic Presence
Despite its mystical applications, the Immaterium is a dangerous realm. No one truly understands why such beings exist, but within the warp lurk dark creatures that feast on the unfortunate souls who are not strong enough to resist the whispers of the warp. These daemons exist only in that mad realm; however, one can summon these daemons through ritualistic sacrifices. When summoned, these daemons assume a metaphysical form that can be killed through normal means, but their souls would be sent back to the Immaterium. A daemon can only be killed through pyschic means.

Imperium of Andarra
The Imperium view psykers with reluctant acceptance. Many fanatics see psykers as an abomination to the Holy Mother's design, bastards of the warpspawns that reside in the Immaterium. Witchhunts are plentiful in the Cardinal Worlds of the Adeptus Ministorum—the Ecclesiarchy—but most of the members of the Senatorum Imperialis realise their strategic value of these pyskers, no matter how risky it may be to keep untrained psykers roaming about the vast territories of the Imperium. A special adepta known as the Adeptus Astra Telepathica was created in .M32 specifically to utilise the pyschic capabilities of these psykers in order to accomplish the Imperium's agenda. These psykers help the innumerable fleets of the Imperium in navigating the dangerous courses of the warp, while also allowing instant communication between one world to another, no matter their distance.