Infinity Circuit

An Infinity Circuit is a psychic network contained in the wraithbone skeleton of an Eldar craftworld. They transmit psychic energy throughout the ship to power on-board devices, and since the fall of the Eldar, they also serve as artificial afterlives for Eldar souls, since otherwise they would be devoured by Slaanesh.

When Eldar die, their souls are trapped by the spirit stones that they wear. These spirit stones are then placed in contact with the core of their craftworld's wraithbone skeleton, which draws the soul out and into the network. The soul's energy is added to the wraithbone's own, while its "personality" finally is laid to rest, safe from Slaanesh forever (as long as the integrity of the circuit itself is maintained—that's what the craftworld's Guardians and other armed forces are for). The hope is that one day, there will be enough psychic energy contained in all of the craftworlds' Infinity Circuits that a new Eldar god will form in the Immaterium, one powerful enough to destroy Slaanesh and save the Eldar race.

Infinity Circuits can also be sources of soldiers. If the need is truly dire, Spiritseers can guide souls out of the Infinity Circuit and back into their spirit stones, which can then be placed into wraithbone constructs like Wraithguard, Wraithlords, Wraithseers, Wraithknights and even tanks to fight for the craftworld once again. Eldar don't like doing this, because they prefer to leave their ancestors in peace, but sometimes it just has to be done. Craftworld Iyanden probably uses the most such "ghost warriors" after sustaining terrible losses against Hive Fleet Kraken; they put themselves through so much angst over it that the Dark Eldar found it funny. Certain tyranids find them delicious.