Clara Oswald

Clara Oswald is a sharp, capable young woman - sometimes a nanny, sometimes a teacher - who keeps turning up in the Doctor's path looking oddly familiar. She's quick-witted, brave to the point of recklessness, and refuses to be talked down to, matching the Doctor barb for barb while clearly itching to see what's out there.

The writing hands Coleman a genuine puzzle-box of a character, and she plays every version with the same crackling confidence, so the mystery never feels like a gimmick standing in for a person. She's funny, unafraid to argue with the Doctor, and grounds even the strangest plots with plain, practical courage.