Eldanesh is a figure from Aeldari Mythology, still revered today by the Craftworld Aeldari, the Asuryani, as the greatest mortal hero of their species who has ever lived. The myth of Eldanesh plays a crucial role in the ceremony known as the Ritual of the Young King that is used to awaken the Avatar of Khaela Mensha Khaine for war on behalf of its Craftworld.
Descendants of Eldanesh amongst the population of the Craftworlds today are said to belong to the House of Eldanesh and are called "Eldanar." They have a longstanding rivalry with those Aeldari who are descended from Eldanesh's former legendary ally and rival, Ulthanesh, the "Ulthanar."
The Tragedy of Eldanesh and Ulthanesh is one of the longest and oldest tales amongst the Aeldari. Due to the complexity of the Aeldari Lexicon, and the extreme reluctance of the Aeldari to speak of their past (or even speak at all) to those they consider "lesser" races, it has never been fully translated into Imperial Gothic. The following text is but an interpretative synopsis of the tale.
Legends say that in the first days of the galaxy, the ruler of the Aeldari pantheon of gods, Asuryan, granted Eldanesh and the other Aeldari the gift of life. The mightiest of the Aeldari gods breathed life into the bodies of all future Aeldari, and was satisfied, but his creations were not. Eldanesh saw the emptiness of the void where only the Aeldari lived, and despaired. Seeing his sadness, the goddess of fertility, Isha, shed a tear for Eldanesh and let it drop upon the material world. It is said by the Aeldari that all other life in the galaxy sprang from Isha's tear, and that the Aeldari rejoiced, for they were no longer alone.
However, new life across the galaxy also meant new threats for the Aeldari race, and they were forced to fend for themselves. Eldanesh rallied his people around him, becoming the first Lord of the Aeldari, and faced the armies of beings known as the Hresh-selain in the Aeldari Lexicon. After many ferocious but inconclusive battles, Eldanesh allied with Ulthanesh, the second-greatest warrior of the Aeldari and the mighty lord of his own noble house, and together the two Aeldari heroes and their people were victorious over the Hresh-selain.
Later, the two collaborated again to fight off the living nightmares known as the Autochtinii. However, their mortal valour proved insufficient, and they only managed to prevail with the help of Kaela Mensha Khaine. It is unclear whether the Aeldari heroes beseeched the help of their God of War and Strife, or if Khaine readily came to the help of his brother Asuryan's creations, but his alliance with the mortal heroes would have terrible consequences.
By accepting the help of Khaela Mensha Khaine, Eldanesh and Ulthanesh had become the first of what would only much later be recognised by the Aeldari of the Craftworlds as Exarchs. Strife had become second nature to them, and soon, Eldanesh's relationship with Ulthanesh became strained. Ulthanesh's ambition and Eldanesh's will always were at odds, but they found themselves unable to reconcile, and Eldanesh ultimately banished his friend into the desert.
Meditating for a long time over the wrongs of the universe and the dishonour visited upon him by Eldanesh, Ulthanesh attempted to recentre his being and find in himself the strength to accept the situation. Yet Kaela Mensha Khaine would not be denied his spoils of conflict: cutting off one of his fingers, the God of War and Strife shaped it in the form of a scorpion and sent it to sting Ulthanesh, knowing that if Ulthanesh died during his exile, the Aeldari would soon know civil war.
Unexpectedly, Ulthanesh survived, and Khaine's plans were almost brought low. But the near-death experience made Ulthanesh realise that he did not need the help of Eldanesh, nor his protection. Returning to his people, he founded the separate House of Ulthanesh and to Khaine's great delight, heralded the age of division for the Aeldari.
Embittered by what he saw as his friend's betrayal, Eldanesh retreated into his role as protector of the Aeldari, and with Khaine still at his side, continued to vanquish their foes. Drunk on the power the mortal granted him through his many victories, Khaine met with Eldanesh in person and promised him not only many more great victories but lordship over all mortal life if only he would abandon the service of Asuryan and swear an oath of loyalty to the God of War and Strife.
Horrified by what he was becoming, and caring more for a peaceful future for his people than an eternity of slaughter, Eldanesh refused Khaine's offer. Enraged that his careful plan for total dominion was falling apart, Khaine struck Eldanesh down with Anaris, one of the divine Swords of Vaul forged by the Aeldari smith god, in a single, fell stroke. This direct intervention of a god in mortal affairs, in direct contradiction of Asuryan's edicts, started a terrible period for the Aeldari Gods known as the War in Heaven.
Ironically, the Houses of Eldanesh and Ulthanesh would unite once more to fight Khaine during this conflict, denying the God of War and Strife total dominion over the galaxy and the Aeldari people. The houses would remain united until the Fall of the Aeldari many Terran millennia later, when the ancient rivalry was sparked anew aboard the Craftworlds of the Asuryani.
As mentioned, this is but one of the interpretations of what Imperial savants managed to learn of the Aeldari's mythic past. However, the Aeldari Lexicon is so full of nuances and seeming contradictions that this interpretation is but one among many possible variants.
In other versions of the tale, for instance, it is told that Eldanesh challenged Khaine to win the freedom of Vaul, the God of Smiths, and that his death at the hands of Khaine ended the War in Heaven instead of starting it. The only event that occurs in all the known versions of the legend, and hence the only parcel taken at face value by Imperial savants, is Eldanesh's death at the hands of Khaine, and Asuryan's condemnation of that act, cursing Khaine's hand to forever more drip with the blood of his mortal victim as a constant reminder of his fell act. It is from that act that Khaine's full name is derived, for the Aeldari term-title Kaela Mensha is translated as "Red Handed" or "Bloody Handed" in Imperial Gothic.
Today, Eldanesh's life and sacrifice 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...
- Warhammer 40,000: Compilation (1st Edition), pp. 36-38
- White Dwarf 127 (US), "Warhammer 40,000 Rogue Trader: Eldar," pp. 14-16
- Path of the Warrior (Novel) by Gav Thorpe, pp. 15, 27, 101, 147, 229, 289