Cortana (Earth-4343)

"This Galaxy is vast; its wonders and beauty are almost unfathomable. But the galaxy also hides dark secrets, some of which have lain dormant since the beginning of time itself. There is a danger in secrets, both in seeking and in knowing. Some things are meant to be hidden from view. Some mysteries defy understanding, and sometimes even the things we think we know are untrue. Some secrets should remain untouched."

- - Cortana to John-117 aboard the drifting Forward Unto Dawn

Cortana (AI serial number CTN 0452-9) was a smart Artificial Intelligence in the service of the United Nations Space Command, assigned to work as John-117's partner in order to commence and complete Operation: RED FLAG, though with the Fall of Reach her true programming would be lost, with she and John fighting for their survival, eventually discovering Installation 04, and after their return to Earth, Installation 05. Unique even amongst other smart AIs, Cortana was created from the brain tissue of Doctor Catherine Halsey herself, soon becoming one of the most important and pivotal figures of the First Contact War. Her tatical prowless proved to be of valuable response, mainly to ensure the survival of Humanity, such as with the Halcyion-class light cruiser Pillar of Autumm and the orbital defense platform Cairo Station. During the final months of the conflict, she also acquired important data about the Quarin and the Halo Array, mainly the activation index of Installation 04.

Allies

 * John-117 - Teammate and Friend
 * Catherine Halsey - Creator