#22 Clara Oswald
Clara Oswald first appeared in the series in Asylum of the Daleks. This episode was the first time viewers realized that the Doctor’s new companion would be unlike any previous companion. In The Name of the Doctor, Clara learns that she was “born to save the Doctor,” prompting her to clone herself and travel to various points in his timeline to protect him from potential dangers.
And as if that weren’t enough, she kept taking the spotlight away from the Doctor and even stole the show from him in a few episodes. Some viewers were annoyed by the spotlight being directed at someone who was only meant to be a sidekick, and the character was soon dubbed “Clara Who.” By the end of season 9, she had even gotten her very own T.A.R.D.I.S.