cortana

The AI companion to the Master Chief in the numbered Halo games.

Cortana is an experimental model physically and mentally based off of her creator, Dr. Catherine Halsey, who also created the SPARTAN supersoldiers.

Cortana is a highly-intelligent individual with a dry sense of humor, and alongside Master Chief, the Arbiter, and Sgt. Avery Johnson, serves as one of the "faces" of the Halo franchise.

Due to her popularity, Microsoft named an assistant AI featured in Windows 8 onwards after Cortana.