Doctor Who show, as the story begins anew with each companion and she undergoes more change than the Doctor. The primary companions of the Ninth and Tenth Doctors were Rose Tyler (Billie Piper), Martha Jones (Freema Agyeman), and Donna Noble (Catherine Tate) with Mickey Smith (Noel Clarke) and Jack Harkness (John Barrowman) recurring as secondary companion figures. The Eleventh Doctor became the first to travel with a married couple, Amy Pond (Karen Gillan) and Rory Williams (Arthur Darvill), whilst out-of-sync meetings with River Song (Alex Kingston) and Clara Oswald (Jenna Coleman) provided ongoing story arcs. The tenth series introduced Pearl Mackie as
Time War (Doctor Who) their demise, the paths between worlds are now closed. The Time Lords could also prevent or repair paradoxes such as the one created by Rose in an attempt to save her father's life in a traffic accident. After the Time Lords' disappearance, such a paradox summons the Reapers, who descended to "sterilise the wound" in time by devouring everything in sight, and are only stopped by Pete Tyler killing himself. Because of the Time Lock, along with the danger of creating a paradox, the Doctor is prevented from going back in time and saving the Time Lords. The Tenth Doctor