Sarah
Another original series companion, Sarah was the companion to the Third and Fourth Doctors, with an appearance alongside the Fifth Doctor in The Five Doctors. She starts out as an investigative journalist, and meets the Doctor during her attempted break-in to a top-secret research facility. She adventures in the TARDIS, assists the UN Intelligence Task Force, and fights Daleks, Sontarans, and Cybermen alongside the Doctor. In fact, she was even present when the Daleks were created. The Doctor and Sarah traveled together for quite some time — four seasons of the show, in fact — before they suddenly parted ways. So, Sarah Jane decided to return to Earth to continue her reporting career. She is one of the most popular companions of the show, with a high number of appearances in Doctor Who and associated spin-offs.
