Kira was, like the star player, a tribal orphan who was taken into Vault 18 as a child and was raised by abusive parents whom she despised. She has a deep hatred for Jennifer Hail, always calling her a "twat". According to Fallout: New California developers, Kira has high functioning aspergers, which is why she has a hard time processing and communicating emotionally.
Resue Me Mann Edit
After completing New California if Kira was the companion of the Star Player, when talking to Jenn in Goodsprings, you'll learn that Kira is now working with the Van Graffs in the Silver Rush. A quest will then be given to rescue her from Jean-Baptiste and Gloria.