Miranda Dawkins

Miranda Dawkins was the ruler of the universe and the Doctor's adopted daughter.

Biography
Her father, the Emperor, was a Time Lord who was the last survivor of a catastrophe that had destroyed his race. When the Emperor was deposed, two members of the Imperial staff spirited the infant Miranda away to Earth in the 1980's to protect her. However, they were discovered, and when her "parents" were killed by the rebels, the Doctor adopted her.

Miranda was known to have at least one adventure with the Doctor during this period of time. (EDA: The Gallifrey Chronicles)

The Doctor raised Miranda until she was sixteen at which point the rebels returned to kill her. However, Miranda ended up killing the leader of the rebels and fled the country. Three years later, she was discovered once again, but managed to reach an understanding with the rebels after she rejected her would-be captor's belief that strength would always prevail. She returned to the future as supreme ruler of the universe. (EDA: Father Time)

Miranda returned to the Doctor's life once more many years later, with a granddaughter named Zezanne. Miranda sacrificed her own life to prevent herself being used as a hostage to stop the Doctor taking action. (EDA: Sometime Never...)

Personality
Miranda was incredibly gifted, compared to the humans on Earth she grew up with. She often had mood swings in her teenage years that caught the Doctor off guard. (EDA: Father Time)