Your Essential Guide to Halo's Lore and Legends
Created by Alex Newhouse on
Cortana is an artificial intelligence entity based on the brain of Dr. Catherine Halsey, the founder of the Spartan program. Cortana was taken off Reach by Noble Squad, and then accompanied Master Chief throughout the events of the four numbered Halo games. She was instrumental in the destruction of the Didact in Halo 4, helping to keep the Promethean attack at bay and ultimately blowing up the Didact's ship and herself.