Cortana

"The Mantle of Responsibility shelters all. But only the Created are its masters."

- Cortana

Cortana is a smart artificial construct and the main antagonist of the Halo 5: Guardians.

In the original Halo trilogy, Cortana serves as a principle protagonist whose role increases dramatically. In Halo 4, she experiences rampancy, causing her to become unstable and volatile until her apparent death. Resurrected in Halo 5: Guardians, Cortana ascends to a higher plain of reality and becomes the most powerful being in the galaxy and the main antagonist of the franchise.

Cortana is voice by Jen Taylor.