Ancilla

Ancillas are a type of Forerunner artificial intelligence construct. They come in several varieties, each designed for different purposes and possessing differing capabilities. Known models include the Monitors, the Contender-class AIs, and the personal ancillas carried by most Forerunners.

Background
Ancillas can be stored within a Forerunner's body armor and can be accessed by the user at will. They can also be housed within personal shells like those of the Monitors, as well as ships, buildings, and various forms of machinery. Ancillas possess varying personalities, often approximating that of a Forerunner; despite this, it is unclear whether their personalities are merely simulated or if they are actually self-aware like human "Smart" AIs.

The most powerful ancillas, next to the Contender-class, are the Metarch-class ancillas which were used exclusively by the Forerunner Council. When a Forerunners is a Manipular, a personal ancilla makes itself easily "visible" and readily accessible to the young Forerunner. But once the Forerunner mutates to first-form, the ancilla makes itself less visible so it can divert power to other tasks, making it much harder for the user to access them. It is also apparent that ancillas help Forerunners access the Domain after mutation. Interestingly, an armor's personal ancilla would assume the form of the species wearing the armor.

Varieties

 * Monitor
 * Metarch
 * Contender-class artificial intelligence

Trivia

 * Bornstellar's relationship with the Librarian's ancilla is similar to that of John-117 and Cortana. Like Cortana, Bornstellar describes his ancilla as a "blue female figure in the back of his mind" who can be stored within his body armor, and relies upon her for guidance and help in many situations.
 * "Ancilla" is Latin for 'female slave', 'female servant' or 'maid'.

List of appearances

 * Halo: The Flood (2010)
 * The Forerunner Saga
 * Halo: Cryptum