Gretchen Carlisle

Gretchen Alison Carlisle was a human soldier who traveled with the Twelfth Doctor, Clara Oswald, Ross and Journey Blue into "Rusty", a Dalek that had turned good, to find out what caused it. They found a crack inside it, which the Doctor fixed, causing "Rusty" to turn back to normal again and contact the other Daleks. The group then planned to turn "Rusty" good again and they split up, with the Doctor going to the Dalek mutant, Clara and Journey going to the memory banks, but Gretchen was killed by the Dalek's antibodies. She then woke up and found herself in a room with a woman who introduced herself as Missy and offered Gretchen tea. (TV: Into the Dalek)