Within this matrix, the souls of all the craftworld's dead reside in a form of group consciousness, providing both a well of psychic power for the worldship and a massive ancestral mind to advise and guide the living.
With the birth of Slaanesh, "She Who Thirsts," the Infinity Circuit is the closest thing that the Asuryani now have to an afterlife; for if their souls are not captured at death in a Spirit Stone and integrated into the Infinity Circuit, they will be lost into the Warp and their soul energy devoured by Slaanesh.
For this reason the Asuryani will defend their craftworlds with a fury and tenacity that is almost unrivaled amongst sentient species; they risk losing not only their home but the souls of their ancestors as well.
The Aeldari souls preserved in the craftworlds' Infinity Circuits can muster only a tiny amount of psychic energy compared to the power that is Slaanesh. Yet the Asuryani believe that one day, when the last Asuryani soul is placed within the craftworlds' collective Infinity Circuits, they will unite into a new Aeldari god known as Ynnead, the god of the dead, who will fight and overthrow Slaanesh, allowing the Aeldari to begin anew. It is a faint hope, but the only one the Aeldari now possess for their dwindling race.
On Craftworld Iyanden, the Infinity Circuit technology was mastered by the Farseer Mehlendri Silversoul at some point in the 33rd Millennium of the Imperial Calendar. She was one of the first of the Aeldari to recover Waystones from the Crone Worlds that were all that remained of the ancient Aeldari Empire and use her allied Bonesingers to adapt them to both contain Aeldari souls and integrate them into an Infinity Circuit.
At the end, Silversoul realised that a soul had to be used to fully awaken the new psychic matrix and she offered up her own, willingly embracing death to offer a new hope of limited immortality to her people. Legend says that she lingers closer to the living world than other souls, and is always the first to welcome Iyanden's newly deceased into the Infinity Circuit's embrace.
It is a psychic gestalt composed of the collective souls of every Aeldari who died on that planet and is very similar in form and function to the Infinity Circuits of the craftworlds.
The World Spirit, like a craftworld's Infinity Circuit, actually has a physical locus on the planet, in this case a global grid of menhirs, obelisks and stone circles called a "World Shrine" that are scattered across the Exodites' planet and all crafted from psychoactive crystal.
These regions are considered sacred by the Exodites and can be used by any psychically-active member of the Aeldari race to commune with the World Spirit, though this interaction is normally only undertaken by a trained Farseer.
- Codex: Eldar (2nd Edition), pp. 6-7
- Codex: Eldar (4th Edition)
- Psychic Awakening: Phoenix Rising (8th Edition), pg. 22
- Warhammer 40,000 Compilation (1st Edition)
- Iyanden: A Codex: Eldar Supplement (6th Edition) (Digital Edition), "Iyanden's Rise and Fall"