Juliana

Juliana was an Insurrectionist "smart" AI operating on the Rubble. She was originally a commercial AI used by miners from the colony of Madrigal. Although her loyalties were to the Rubble, she consented to ally with the UNSC in order to save the Rubble and its citizens. When she met the Gray Team, she was going through stages of rampancy, yet didn't seem to be showing it. As she said, she hung onto the edge of rampancy, trying to go back.

History
The Rubble was coexisting with a group of Kig-Yar who were secretly trying to find the navigation data that would provide them Earth's coordinates. In order to prevent this, Juliana helped members of Gray Team recover the navigation data, rescue Lieutenant Jacob Keyes and the ODSTs, and evacuate the citizens of the Rubble to the Exodus Project. Juliana who had already been rampant for some time, offered to drive the remains of the Rubble down onto the surface of Metisette.

Personality
Despite having been rampant for some time, Juliana did not engage in aggressive or destructive behavior like some AIs. The reason for this being that, like she said, the Rubble meant so much to her that the necessity of keeping it running and thriving held her sanity together. Certain elements of her behavior strongly pointed to rampancy, however, such as a somewhat egotistical sense of greatness to the Rubble. This was not exaggerated, but her manner of thinking of herself as almost a god was unusual. Her taking a strong liking to Jai, the Spartan leader of Gray Team is somewhat strange as well. Little is known of her personality before she went rampant.

Trivia

 * Her character's role is surprisingly similar to Sif's from the previous book, Contact Harvest. Both are AIs that are or eventually end up rampant and sacrifice themselves aboard space stations, the Tiara for Sif, and the Rubble for Juliana ultimately for the better of the UNSC forces nearby. Cortana also went rampant, but held onto enough control to defeat the Ur-Didact and protect Earth before being destroyed.
 * Juliana held the safety of the Rubble higher than any personal interest of the leading council. Despite the council's ruling to be given the navigation data, she helped Gray Team to retrieve the data and rescue the ODSTs from confinement, also another action against the ruling of the council.

List of appearances

 * Halo: The Cole Protocol