Cast

A cast was a type of weapon created by the Great Houses to act as their agents for performing hazardous activities in the outside universe. They were considered the Homeworld's "first line of defense".

Insubstantial and mindless, they were hardwired into the Homeworld's noosphere or the operating system of a timeship. When activated, the cast would manifest itself by absorbing radiation from the vicinity and changing it into solid baryonic matter or invisible, lower-dimensional strange matter. Most casts were programmed with only simple instructions, though it was possible to give them near-sentience in emergencies.

Though the casts lulled the Homeworld into a sense of security, when they were put to the test during the War in Heaven, they were found to be effectively useless against the conceptual entities which they somewhat resembled. During the enemy's initial assault on the Homeworld, most casts were destroyed, and even the survivors suffered from a broken connection to the noosphere and the caldera, leaving them as empty ghosts to haunt their timeships and Houses. Seventy-three casts were used during the Lethean Campaign, but they and their timeships were easily destroyed by the enemy's ship-eater weapons.

The babels were created during the Catherion Imprimiture as a more advanced second generation of the casts. (PROSE: The Book of the War)

Behind the scenes

• The character Shayde from the Doctor Who Magazine comics closely resembles The Book of the War's descriptions of the casts.