Television
Oswin Oswald (Jenna Coleman) is introduced in the series 7 premiere, "Asylum of the Daleks" (2012). She is the sole survivor of the starship Alaska, which crashed on the Asylum, a prison planet for insane Daleks. Oswin sees herself as human, but the Eleventh Doctor (Matt Smith) discovers that she was converted into a Dalek and coped by dreaming that she is still human. She sacrifices herself to help the Doctor and his travelling companions, Amy Pond (Karen Gillan) and Rory Williams (Arthur Darvill), escape the planet unharmed. In the 2012 Christmas special "The Snowmen", the Doctor meets a Victorian barmaid and governess named Clara Oswin Oswald (Coleman), whom he initially knows only as Clara. He invites her to be his newest companion but she is killed by one of the Great Intelligence's minions. Seeing her full name on her tombstone and finally recognising her voice, the Doctor realises Clara and Oswin are somehow the same woman. He begins searching across time for another Clara. Unknown to the Doctor, another incarnation of Clara Oswald (Coleman) is introduced living in 2010s London.
In "The Bells of Saint John" (2013), Clara inadvertently calls the Doctor, having received the phone number for his time machine, the TARDIS, from a mysterious woman. The Doctor takes her on as a companion with a goal to solving the mystery of her multiple lives—he nicknames her the "impossible girl". The Doctor's attempts at investigating her origins over the course of "The Rings of Akhaten", "Hide", and "Journey to the Centre of the TARDIS" consistently turn up compelling evidence that she is a normal human woman. In "Journey to the Centre of the TARDIS", the Doctor confronts Clara in an averted timeline about the two previous versions of her he had met, but she has no knowledge of this. The mystery is resolved in "The Name of the Doctor" when Clara sacrifices her existence by entering the Doctor's timestream to undo harm caused by the Great Intelligence (Richard E Grant). This creates numerous "echoes" of Clara throughout the Doctor's past history who save his life in numerous ways. One version of Clara successfully persuades the First Doctor (William Hartnell) to pick the "right" TARDIS on his home planet Gallifrey, prior to the events of An Unearthly Child (1963). Clara is lost in the Doctor's timestream but he manages to bring her back into existence. By "The Day of the Doctor", the series's 50th anniversary special, Clara has become a teacher at Coal Hill School. She meets the Doctor's earlier incarnations, the Tenth Doctor (David Tennant) and the War Doctor (John Hurt), the latter of which had annihilated Gallifrey and his people, the Time Lords, to end the destructive Time War. Upset by this action, Clara convinces the Doctor to rewrite history, and he instead seals the planet in a pocket universe. In "The Time of the Doctor", the Time Lords try to return to the universe through a crack in time located on the planet Trenzalore. Knowing that the Time Lords' return will reignite the Time War, the Doctor sends Clara home to her family at Christmas twice while he stays on Trenzalore. Clara returns in the TARDIS each time after two centuries-long intervals. With the Doctor facing certain death at the end of his regeneration cycle, she pleads with the Time Lords to save the Doctor; they grant him a new regeneration cycle and the crack closes.Clara witnesses the Eleventh Doctor regenerate into the Twelfth Doctor (Peter Capaldi). She grapples with losing the Doctor she knew and loved throughout the events of "Deep Breath" (2014), even considering refusing to travel with him, until a phone call from the Eleventh Doctor prior to his regeneration convinces her to stay by the Doctor's side and help him adjust to his new persona. In "Into the Dalek", Clara and fellow teacher Danny Pink (Samuel Anderson) agree to go for drinks together, and over the course of the episodes "Listen", "Time Heist", and "The Caretaker", the two enter into a romantic relationship. Clara keeps secrets between the Doctor and Danny due to their misgivings about each other. She experiences turbulence in her friendship with the Doctor, particularly in "Kill the Moon" when he abandons her to face a traumatic decision on her own. In "Flatline", she is forced to take the Doctor's role in averting an alien invasion, and realises she is capable of making the same ruthless and pragmatic decisions he often has to make. In "Dark Water", Danny dies in a traffic collision before Clara can announce her intent to commit to him fully. She attempts to threaten the Doctor into changing history to avert Danny's death. Despite her betrayal of the Doctor, he agrees to help her contact Danny from beyond the grave. They discover a facility where evil Time Lord Missy (Michelle Gomez) has stored the consciousnesses of Earth's dead as part of a plot to convert the deceased into a Cyberman army. In "Death in Heaven", Missy reveals that she was the aforementioned woman who gave Clara the TARDIS phone number. Danny is brought back as a Cyberman but he resists his programming in order to destroy Missy's Cyberman army and foil her plans. Two weeks later, Clara and the Doctor meet to farewell each another. The Doctor lies to Clara; he pretends he has found Gallifrey and a home to go back to. Clara lies too; she pretends Danny returned from the dead through Missy's device, when in fact he sacrificed the opportunity to save the life of a child he killed in the Afghanistan war.Clara reunites with the Doctor in the 2014 Christmas special "Last Christmas", when aliens trap them in a shared dream. Clara dreams that Danny is still alive, but realises it is not real. She admits Danny is dead, while the Doctor confesses he did not find Gallifrey. After waking, they reconcile and Clara agrees to travel with the Doctor again. In series 9, Clara accompanies Missy and the Doctor to Skaro when he is summoned by Davros (Julian Bleach), barely escaping the ordeal with her life. Now an experienced space traveller, Clara shows greater confidence when dealing with alien races and volatile humans, but the Doctor finds himself concerned by her reckless streak. In "The Girl Who Died", Clara and the Doctor use alien technology to resurrect Ashildr (Maisie Williams), a Viking killed during their successful attempt to save her village, but inadvertently give her immortality. Clara's recklessness gets the better of her in "Face the Raven". Her friend Rigsy (Joivan Wade) is sentenced to death by a Quantum Shade (a raven-like being), and is given a numerical tattoo which counts down to his death. Clara convinces him to transfer the tattoo to her, but later learns that this breaks the Shade's contract, making the death sentence irrevokable. Clara cautions the Doctor not to give in to his darker nature in response to her death, which she faces with bravery.
In "Heaven Sent", a grief-stricken Doctor imagines conversations with Clara to clarify his ideas. In "Hell Bent", the Doctor uses Time Lord technology on Gallifrey to extract Clara from her last moments of life. As a result, her biological processes are frozen: she does not have a heartbeat and cannot age. The Doctor plans to return Clara to Earth where she can live a normal life, and he prepares to wipe her memories of him so that the Time Lords cannot use her to find him. Clara tampers with the mind-wiping device so that it wipes the Doctor's memories of her instead. She leaves the Doctor on Earth by the TARDIS to start his adventures anew. Clara tells Ashildr that she intends to one day visit Gallifrey and return to the moment of her death, but vows to take "the long way around". She and Ashildr begin traveling the universe together in a TARDIS stolen from Gallifrey.
In "Twice Upon a Time", the Doctor encounters Testimony, a futuristic organisation which copies people's memories at the moment of death and installs them in sentient avatars. An avatar of the Doctor's companion Bill Potts (Pearl Mackie) restores his memories of Clara; he sees a mental image of her telling him not to forget her again.
In the 60th anniversary special episode "The Giggle", the Toymaker depicts Clara as a marionette alongside Amy and Bill, taunting the Fourteenth Doctor by reminding him of companions who died while travelling with him.