I am a mysterious archaeologist and convicted murderer who shared a close relationship with the Doctor. Significantly, I was the only companion who knew the Doctor's true name that he told me at some point in his future for reasons as of yet undisclosed. I would often greet him by saying "Hello, sweetie" whether it be on a message or in person.
I liked to constantly annoy the Doctor by showing off my knowledge in front of him, acting as though I knew better than him, and knew him better than himself. I would often use the word "spoilers" whenever the Doctor and I gave each other hints or facts about the other's future. I would constantly keep usually giving the answer of , which I also used when a fact about my own future was revealed. I was also adept at keeping secrets from the Doctor, especially anything which would interfere or change the future,
including keeping my personal diary from him.
Personality
At times I enjoyed showing off my knowledge in front of the Doctor, particularly knowledge of him and his personality. I would often use the word "spoilers" in reference to my knowledge of the Doctor's future, or his knowledge of my future. I was also persistent at keeping secrets from the Doctor, especially anything which could change the future. This included keeping my personal diary from him.
I showed that I cared about other people, such as the Doctor and my team in The Library, but could also demonstrate signs of mercilessness, such as killing the Stone Dalek after it had shot the Doctor and begged for mercy showing a fear of me when it learned who I was. I could be cheeky, but was serious when the situation called for it.