Ancillary

An ancillary is a human body which is controlled by a ship. Ancillaries serve as ground troops and domestic servants to a ship's officers as well as their direct connection to the ship's AI. Ancillaries are considered disposable and easier to maintain than human troops, because they can be left in suspension pods indefinitely and ships typically store more ancillaries than they need.

Before the events of Ancillary Justice, the Radch created ancillaries from people captured during annexations, but the capture of more people was outlawed by the pro-reform Anaander Mianaai, so only bodies already held in storage can be used for the process. The process of creating ancillaries involves thawing out a body from the ship's hold and using surgery and implants to destroy "the body's sense of identity" and modify the brain to perceive itself as part of the ship . Afterwards, an ancillary body will typically experience nausea and anxiety for up to two weeks, but some segments never adjust and are removed and replaced. Communication technology allows the ships to receive sensory information from its ancillaries in real-time and make some decisions for them . It is possible to disrupt an ancillary's connection to the AI; this is distressing for them, but they can continue to function as independently until connection is restored. Prolonged disconnection can lead to divergence between the ship and its ancillaries .

Excluding communication disruptions, ancillaries are not individuals and act as segments of a multi-bodied sub-entity of the ship called a unit. Units may have up to ten or twenty segments, depending on the class of the ship; Justice-class ships have twenty-segment per unit while Mercies and Swords have twenty-segment units serving the captain and ten-segment units for officers. Units are assigned to serve a particular decade and are named after the decade they serve. Justice-class ships have multiple units per decade and each unit is numbered. Individual segments within a unit are also numbered. A segment's full designation is the name of the ship, unit number, decade, and finally the individual number within the segment. Breq was formerly the segment Justice of Toren One Esk Nineteen.

While units are part of a ship, they can have unique personality traits and interests separate as long as the ship allows it. In Ancillary Justice, Breq states that One Esk learned to sing to please a lieutenant while Justice of Toren only tolerated One Esk's habit of singing. The Esk lieutenants also note that Two Esk did not sing.