From Destinypedia, the Destiny wiki
Ether is a white, gaseous substance that Fallen depend on to survive, and which only Servitors can currently produce. Ether Seeds may be processed Ether for later usage or storage, and Ether Drops are ether remnants.
Ether is a cold, glowing white gaseous or liquid substance, created by Servitors from matter and energy (organic compounds, in one known case) through an unknown process. It is absorbed through breathing , and appears to run through Fallen bodies like blood. It can be consumed by other beings as well. When there is enough in quality it fills an Eliksni with strength. 
Ether was once freely available on the Eliksni homeworld of Riis but is now strictly rationed according to rank. Kells hold a device called The Elder Cipher, which controls how much Ether is distributed from Servitors; Archons and Barons get an exceedingly large portion while Dregs get only enough to stay alive. This rationing stunts the potential strength and size of contemporary Fallen, particularly the lower ranks.
Beyond merely providing nourishment, Ether is hypothesized to be an "ethereal lifeblood" for the Fallen, but not a "soul" as is commonly assumed, though it can be used to restore the souls of other Fallen. When a Fallen is killed in combat, a momentary after-image of their body composed of Ether may briefly be seen. The significance of this remains unclear.
Ether is poisonous to Hive, although it is possible for Hive to grow tolerant of Ether through breeding processes, as a Knight possessed Ether inside him due to experimentation by Hiraks, the Mindbender.
In humans, Ether appears to have properties similar to that of a recreational drug, though it can lead to an unpleasant experience according to the Drifter, or possibly even poisoning, though no permanent damage can occur according to Failsafe.
During the Red War, the Fallen House of Dusk was able to utilize stolen Cabal technology and the Servitor Serkuleks, the Fount to create a modified, more effective form of Ether known as "Enhanced Ether". Those who took this Ether substance would become Empyrean Fallen, exhibiting several effects including increased strength and health, and the side-effect of glowing like Servitors. Raksil, Archon Priest would head this operation before being killed. The project would later be put to a complete end following the destruction of Serkuleks at the Guardian's hands.
The Scorn thrive off of Dark Ether, a disturbing, corrupted form of Ether derived from remnants of the Darkness afflicted within Uldren Sov from his experience during the Battle of Saturn. After wishing to save a dying Fikrul, which is fulfilled by the Ahamkara Riven, some of the Darkness within Uldren was transferred into Fikrul's lingering Ether, bringing the disgraced Fallen back from death and creating Dark Ether.
Dark Ether is capable of resurrecting dead Fallen at the cost of severely mutating them, such as how the Screeb units of the Scorn have been warped into hexapod Thrall-like monstrosities. It lingers instead of dissipating like normal Ether and is described by Variks as a fog-like gas that you move through like water, heavy and opaque.
- In Destiny killing Fallen with headshots causes a torrent of Ether to erupt from their heads. In Destiny 2 this takes the form of a momentary, ghostly silhouette of the dead Fallen.
- Ethers are a class of organic compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula R–O–R′, where R and R′ represent the alkyl or aryl groups.
- Dimethyl ether is the organic compound with the formula CH₃OCH₃, simplified to C₂H₆O. The simplest ether, it is a colorless gas that is a useful precursor to other organic compounds and an aerosol propellant that is currently being demonstrated for use in a variety of fuel applications. It is an isomer of ethanol.
- In literary, ether mean the clear sky; the upper regions of air beyond the clouds.
- In Archaic physics, ether is a very rarefied and highly elastic substance formerly believed to permeate all space, including the interstices between the particles of matter, and to be the medium whose vibrations constituted light and other electromagnetic radiation.
- In Greek mythology, Ether is the personification of the bright upper sky. According to Hesiod, he was the son of Erebus (Darkness) and Nyx (Night), and the brother of Hemera (Day).
- In the lore of the "A Thousand Wings" Jumpship in Destiny 2, the Ether is called the Fallen's demiurge (Which equates to Survival).
- During Destiny 1, Fallen Servitors were able to heal and buff Shanks like any normal fallen, even being able to heal other nearby Servitors as well. It is unknown if it was intentional or not.
List of appearances
- Bungie (2014/9/9), Destiny: Playstation 4, Activision Blizzard
- Bungie (2014-9-9), Destiny, PlayStation 4, Activision Blizzard, Grimoire: Servitor
- Bungie (2014/9/9), Destiny: Playstation 4, Activision Blizzard, "The Queen wishes to know all she can about the Fallen. Collect samples of Fallen Ether from the enemy dead", Relic Harvest - Fallen
- Bungie (2014/5/19),Destiny: House of Wolves Playstation 4, Activision Blizzard, Grimoire:
- Bungie (2015/9/15), Destiny: The Taken King Playstation 4, Activision Blizzard, Grimoire: Rezyl Azzir - War Without End
- Bungie (2014/5/19), Destiny: House of Wolves Playstation 4, Activision Blizzard, Grimoire: Kaliks Reborn
- Bungie (2014/5/19), Destiny: House of Wolves Playstation 4, Activision Blizzard, Grimoire: WANTED: Beltrik, the Veiled
- Bungie (2014/5/19), Destiny: House of Wolves Playstation 4, Activision Blizzard, Grimoire: Ghost Fragment: Fallen 3
- Bungie (2014-9-9), Destiny, PlayStation 4, Activision Blizzard, Grimoire: Ghost Fragment: Hunter
- Bungie (2014/5/19), Destiny: House of Wolves Playstation 4, Activision Blizzard, Grimoire: Skolas: Captured
- Mystery: The Fate of Skolas
- Bungie (2014-9-9), Destiny, PlayStation 4, Activision Blizzard, Grimoire: Captain
- Bungie (2014/12/9), Destiny: The Dark Below Playstation 4, Activision Blizzard, "Kell uses Ciphers to control the Ether flow. Archons and Barons take deep draughts, grow tall. Dregs with tiny sips stay small", The Elder Cipher
- Bungie (2014/12/9), Destiny: The Dark Below Playstation 4, Activision Blizzard, "The gas is no soul. An ethereal lifeblood, maybe, but a soul? I think not", Kellbreaker's Gloves
- Winter's Run
- Bungie (2014/5/19), Destiny: House of Wolves Playstation 4, Activision Blizzard, Grimoire: WANTED: Ether Runner
- Bungie (2016/20/9), Destiny: Rise of Iron Playstation 4, Activision Blizzard, Grimoire: Ghost Fragment: Fallen 5
- Bungie (2014/9/9), Destiny: Playstation 4, Activision Blizzard, Grimoire: Sepiks Prime
- Bungie (2018/9/4), Destiny 2: Forsaken, Playstation 4, Activision Blizzard, Broodhold
- Bungie (2018/9/4), Destiny 2: Forsaken, Playstation 4, Activision Blizzard, The Forsaken Prince
- Bungie (2020/6/9), Destiny 2: Season of Arrivals, Playstation 4, Activision Blizzard, Item Description: Ether Ventilation
- Bungie (2017/9/8), Destiny 2: Playstation 4, Activision Blizzard, Failsafe: Did you know Ether exposure causes no permanent damage? Congratulations!
- Bungie (2017/8/9), Destiny 2: Playstation 4, Activision Blizzard World Quest: Enhance!