In addition, she held vital data pertaining to the Halos , including the Activation Index from Installation Cortana in a holotank, analyzing the Forerunner artifact under Sword Base. Cortana was created using a flash cloned copy of Dr. Catherine Halsey 's brain. Twenty flash cloned brains were created, but only two survived; one of the two survivors was used to create Cortana.
Meet the actress behind everyone’s favorite AI, Halo’s Cortana
Cortana - Character - Halopedia, the Halo wiki
Halo TV show brings back original Cortana actress
Cortana is one of the Halo series' biggest characters, second only to Master Chief himself. Appearing in the vast majority of all Halo media, not just the games, she has become so important that she is literally Microsoft's version of Siri. Despite all the fame and popularity, a lot of the details about this character remain a mystery, even to a decent portion of Halo fans.
Reach . November 7, . Unique and exceptionally powerful even among smart AIs,  she was one of the most important figures in the Human-Covenant War , and served as John 's partner in the final months of the conflict.