Clara Oswald

Oswin Oswald was a human serving as a Junior Entertainment Manager onboard the starship Alaska when it crashed into the Dalek Asylum.

Biography
Oswald initially tried to escape the Asylum but was found and converted into a Dalek. Unlike other members of the Alaska, who were partially converted by the nanocloud, she was fully converted, due to her intelligence. In Dalek form she created a dream world for her human mind to dwell in to forget the truth. Under this life, she assumed that she was surviving on soufflés and hacked into Dalek systems.

A year later, she aided the Eleventh Doctor, Amy and Rory in finding safe passage, wiping the memory of the Doctor from the Daleks' telepathic web in the process to save him. The Doctor attempted to rescue her, but discovered she was a Dalek and revealed it to her. Oswin first attempted to exterminate the Doctor, then broke down over what she had become.

Oswin lowered the Asylum's defenses so the Parliament of the Daleks could destroy the planet, and Amy, Rory and the Doctor could escape back there, to find out that Oswin had erased the Doctor from the memories, not only of the ones in the Asylum, but of every single Dalek. (DW: Asylum of the Daleks)