Emily Winter

Emily Winter, a film actress in 1920s-era Hollywood, travelled with the Tenth Doctor as his companion after an incident in which her mind was taken over. (IDW: Silver Scream, Fugitive) Formerly a meek and mild actress, following this event she became hardened, with violent tendencies, and insisted the Doctor give her a weapon (which he refused). (IDW: Tesseract)

Behind the scenes

 * Emily's behaviour starting in Tesseract is reminiscent of Ace from the TV series.