Kait was the daughter of Reyna Diaz and the niece of Oscar Diaz. Born after the end of the Locust War, Kait's mother fled from the re-organized COG and raised Kait within the community of Outsiders, keeping her away from the COG's propaganda system and other policies. Kait was taught how to shoot and fight from her uncle Oscar, while she received an informal education through salvaged books that her father had saved from the libraries of Montevado and Ilima before the two cities were utterly destroyed during the Locust War.