This term is most often applied to the physical body possessed by a fragment of the spirit of the Aeldari God of War and Strife Kaela Mensha Khaine, though the term can actually apply to any divine entity of the Warp that has found some way to take on a corporeal form on the mortal plane of existence.
By far the most well-known Avatar is that of Khaine, but recently a new Aeldari god, Ynnead, the God of the Dead, has begun to awaken. Ynnead also has an Avatar in the material world, known as the Yncarne.
Avatar of Khaine
At the heart of every Craftworld sits the Avatar, its own incarnation of the Bloody-Handed God of the Aeldari, Kaela Mensha Khaine. Aroused from his throne of smouldering iron, the Avatar leads the warriors of his Craftworld to battle. Huge and all-powerful, the Avatar is a god incarnate, the embodiment of the Aeldari racial soul, and a deadly opponent even for the most mighty powers of Chaos.
It is said that after the birth of the Chaos God Slaanesh, "She Who Thirsts," during the Fall of the Aeldari in the 30th Millennium, she fought and killed the ancient Aeldari gods one-by-one in the Immaterium, absorbing their essences into her own just as she had the souls of the Aeldari themselves. But the God of War and Strife, Khaela Mensha Khaine, was too strong to be destroyed forever. So Khaine's spirit fled the Warp and found refuge dispersed among the Infinity Circuits, the psychically-reactive Wraithbone hearts of the remaining Aeldari Craftworlds.
Wherever his essence landed, a Wraithbone artefact in the form of a great statue of the god was created, allowing future Aeldari to be able to summon a fragment of the spirit of Khaine back into the Materium to defend his race when a Craftworld faces a particularly dire crisis.
These fragments of his spirit can be summoned into realspace in times of great danger by the Aeldari from the Infinity Circuit where they rest to inhabit a physical body that will fight on their behalf. These are the Avatars, a single fragment of a true Aeldari god. The Aeldari of the Craftworld call forth the Avatar in times of dire need by sacrificing an Exarch to Kaela Mensha Khaine on the eve of battle. The Avatar becomes a fiery, animated manifestation of the god in the wake of this blood sacrifice and leads the Aeldari armies into battle.
Ritual of the Young King
The sacrifice of the ancient mythological Aeldari culture hero Eldanesh, who allowed himself to be slain by Khaine rather than serve the war god and bring all of the Aeldari under his dominion, is still honoured amongst the Craftworld Aeldari when they need to go to war. As the call-to-arms rouses the Aspect Warriors and Guardians, a Craftworld's Infinity Circuit will gather all the excess psychic aggression and hatred of its denizens and channel it into the metal body of Khaine's Avatar, to empower it for its eventual possession by the God of War and Strife's soul shard that lies dormant within the Infinity Circuit of every Craftworld.
The Ritual of the Young King is the final step necessary to entreat the shard of Khaine to enter his Avatar's body and march forth to war. It has minor variations on each Craftworld, but in essence it remains the same: one of the Craftworld's Exarchs will embody the Young King Eldanesh as he refuses Khaine's offer of dominion over the universe. This brutal reminder of his greatest failure will so enrage the fragment of the god in the Craftworld's Infinity Circuit that it will enter the prepared vessel and slay the impudent mortal once again.
As with everything amongst the Aeldari, this event is highly ritualised to prevent any psychic overspill attracting the attention of Slaanesh. First, the Exarchs will choose amongst themselves who will be the Young King. The method of the choice differs from Craftworld to Craftworld. Some have the Exarchs rotating through the position during a fixed timespan, others see the Exarchs choose who amongst them will receive the honour just before the awakening by ritualised combat.
Once an Exarch is chosen, he or she becomes the Young King. The gender matters not, and a female will still be referred to as the "Young King," for she embodies Eldanesh, and Eldanesh was male. When the Ritual of the Young King reaches the moment for awakening the Avatar, the other Exarchs will gather in the antechamber of Khaine's shrine and form a circle around the Young King, softly chanting. They will solemnly assist the Young King in removing his or her Exarch Armour, which will reverently be returned to its Aspect Shrine.
Once this is done, the Young King will stand tall, completely naked, arms spread wide and head bent backwards in adoration while the most senior Exarch of each Aspect carves the rune of its Aspect of War in the Young King's back. On some Craftworlds, a golden cup called the Chalice of Criel is held to the small of the Young King's back to collect his blood, while on others, it is allowed to flow freely, anointing the ground of Khaine's shrine.
Once all the runes have been carved into the Young King's back, the Exarchs will bring forth the Suin Daellae, the "Howling Death," the gigantic spear or sword that serves as the weapon of the Avatar of Khaine. The Young King will take the Suin Daellae while the remaining ornaments are brought and placed upon him; most often these are a cloak and a simple garland of flowers.
If the Chalice of Criel is used in the ritual, it will be presented to the Young King who will take a sip of his own blood before accepting the cup. Once the preparations are completed, the doors to the inner sanctum of the shrine will be opened, and the Young King will step forth carrying the Avatar's weapon. The doors will close behind him and the Exarchs will offer a hymn of praise to Khaine and thanks to the Young King for his or her sacrifice.
What exactly happens in the inner sanctum, none knows, for no Young King has ever lived to speak of it. But inevitably, after a few moments, the doors will open again, and the Avatar, fully empowered, will march to war. Of the Young King, no trace, save perhaps the dripping blood on the hands of the Avatar, will remain...
- The Wailing Doom - Each Avatar of Khaine carries a mighty weapon, known in the Aeldari Lexicon as the Suin Daellae, the Wailing Doom. This massive blade is many feet long, and shrieks as it tastes mortal flesh, wailing and crying and hurling murderous bolts of force as the Avatar strides to war and reaps a brutal tally at close quarters. Upon its surface, ancient runes writhes as they struggle to escape from their bondage as if tortured by the heat of the Avatar's grasp. The Wailing Doom is no mortal weapon, but the manifestation of a dark and sinister god -- a part of the Avatar imbued with his divine power.
Avatar of Ynnead
The Aeldari God of the Dead Ynnead is a dream, the embodiment of a possibility that has yet to be fully realised. Some Asuryani Seers long believed that when the last Aeldari died during the Rhana Dandra (the Final Battle with Chaos), Ynnead will be born from the Warp with the strength of all the Asuryani souls stored in the Infinity Circuits of the Craftworlds and the World Spirits of the Exodites. Ynnead will then have the power to destroy Slaanesh forever in a final battle, thus correcting the mistakes which led to the Fall of the Aeldari and allowing the race to be reincarnated into a universe free of the taint of Chaos.
Or at least that is what the Asuryani believed would happen for almost ten thousand standard years. Then, in 999.M41, during the Battle of Port Demesnus on the moon of Coheria, the High Farseer Eldrad Ulthran of Craftworld Ulthwé partially completed a ritual intended to awaken Ynnead using the power of the souls found in the Infinity Circuits of every Craftworld in the galaxy.
While the unexpected intervention of the Imperial Deathwatch interrupted the ritual before it could be completed, the God of the Dead was partially awakened, and sought out a champion and prophet to complete his rise in the form of Yvraine, the Daughter of Shades. Yvraine founded a new Aeldari faction dedicated to the Whispering God's resurrection known as the Ynnari.
The Ynnari, with members drawn from the Craftworld Asuryani, the Harlequins, and the Drukhari of Commorragh, seek the restoration of the ancient Aeldari race and the full awakening of the God of the Dead by collecting the artefacts known as the Croneswords from across the galaxy. Their combined ritualistic use at a single focused point in realspace will allow Ynnead to fully manifest his power in the Warp, where he will combat Slaanesh, hopefully destroying the Prince of Chaos and freeing the Aeldari from the soul-devouring curse of She Who Thirsts forever. Only then will the Aeldari race, restored to the unity and name of the ancient Aeldari, seek to rebuild a new and better interstellar empire.
Imperium of Man
While only the Aeldari have actually made use of physical Avatars to date, the Thorian faction of the Inquisition searches for the Avatar of the Emperor of Mankind who they believe will actually be born somewhere in the galaxy at the time of the greatest need for the human race among the teeming billions of the Imperium of Man. There are numerous factions within the Adeptus Mechanicus, including the Khamrians, who pursue the forbidden science of artificial, or "abominable" intelligence. The Omnissiads of the Cult Mechanicus seek to summon the Machine God into an Avatar called the Omnissiah. In the early days of the Great Crusade, the Emperor of Mankind was recognised as the Omnissiah by the leaders of the Adeptus Mechanicus, prompting the Treaty of Mars and the alliance of the Cult Mechanicus with the nascent Imperium of Man, but the Omnissiads refuse to recognise the Emperor as this physical extension of the Machine God, and instead create their own.
- Codex: Eldar (6th Edition), pp. 7-8, 26
- Codex: Eldar (4th Edition), pp. 6, 9, 11, 24-25
- Codex: Eldar (3rd Edition), pg. 8, 17
- Codex: Eldar (2nd Edition), pp. 4, 7, 15, 22, 33, 56, 72, 85
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