Christina

Christina is a companion of the Twelfth Doctor, and the third overall. She meets the Doctor in The Girl and the Monster when he saves her from the clutches of the Slitheen Fell Blotch Dreg, masquerading as the local MP Andrew MacCoffey and also trying to make Christina his bride.

Background
Christina never fully reveals her last name, and simply goes by Christina. She is 26, and works as a secretary in South London for Andrew MaCoffey, who is really the Slitheen Fell Blotch Dreg.

Personality
Unlike the Doctor's previous female companion Isabella Cartwright, Christina is outgoing and speaks her mind. She is very knowledgeable, and can help the Doctor in many scientific and mechanical situations. Her reaction to the Daleks (The Survival of the Daleks, The New Breed) is at the most terrified, although she does not have any fear standing up to them. The Dalek Pariah likens her to the Doctor's companion Romana.