Catherine Elza Halsey (Earth-2042)

"For a long time I had thought that we had to sacrifice a few for the good of the entire galaxy. I have killed and maimed and caused a great deal of suffering to many people—all in the name of self-preservation. But now I'm not sure that philosophy has worked out too well. I should have been trying to save every single life—no matter what it cost."

- Dr. Catherine Halsey to John-117 regarding her changed views

Doctor Catherine Elizabeth Halsey, phonetically identified as "Charlie Hotel", is a female Human and former key scientific adviser of the Office of Imperial Intelligence as well as its predecessor, the Office of Naval Intelligence, best known for her work with the SPARTAN-II Program, developing and creating droids and smart AIs such as Cortana, and for overseeing the development of the MJOLNIR Powered Assault Armor. She served as a scientific advisor for ONI and OII from the last decades of the Galactic Republic to the end of the Galactic Empire, when she was made chief scientist, a position she held until the end of the Galactic Civil War before her arrest by the New Republic.

Source

 * https://www.halopedia.org/Catherine_Halsey