Every Eldar Craftworld contains an Infinity Circuit, which is essentially 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 rise of Slaanesh, the Infinity Circuit is the closest thing that the Eldar have to an afterlife; if their souls are not caught and integrated into it, they will be lost into the warp and devoured by the Great Enemy. For this reason the Eldar will defend their Craftworlds with a fury and tenacity almost unrivalled; they risk losing not only their home but the souls of their ancestors as well.
Although the Eldar souls preserved in the Craftworlds' Infinity Circuits can muster only a tiny amount of energy compared to that of Slaanesh, the Eldar hope that one day there will be enough souls to unite to fight and overthrow Slaanesh. It is a faint hope, but the only hope for the Eldar who otherwise face damnation and extinction from their own racial daemon.