An Infinity Circuit is a psychic matrix contained in all Eldar Craftworlds, and is essentially composed of the Wraithbone skeleton of the Craftworld itself. 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 ship 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 Eldar now have to an afterlife; for if their souls are not captured at death and integrated into the Infinity Circuit, they will be lost into the Warp and devoured by Slaanesh. For this reason the Eldar 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 Eldar 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 Eldar believe that one day, when the last Eldar soul is placed within the Craftworlds' collective Infinity Circuits, they will unite into a new Eldar God known as Ynnead, the God of Rebirth, who will fight and overthrow Slaanesh, allowing the Eldar to begin anew. It is a faint hope, but the only one the Eldar now possess for their dwindling race.
- Codex: Eldar (2nd Edition), pp. 6-7
- Codex: Eldar (4th Edition)
- Warhammer 40,000 Compilation (1st Edition)