Susan (Dr. Who and the Daleks)

Susan was the granddaughter of the human scientist Dr. Who.

Biography
Susan accompanied him on his first trip to the planet Skaro in TARDIS, where she met the Daleks and then an ancient Roman legion (Dr. Who and the Daleks). Later she went on a trip with him to the devastated London of 2150, which the Daleks had invaded. (Daleks' Invasion Earth 2150 A.D.) Once again, they fought the Daleks, this time on Mars (DWM: Daleks Versus the Martians)

Susan shared her grandfather's genius and passion for science, and this contributed to her being a highly precocious child.

Behind the scenes

 * Susan was based on the the Doctor's granddaughter Susan Foreman, who was an older and almost entirely different character. While a few reference works indicate that Susan's full name is Susan Who, this is not supported by any on-screen evidence. On-screen, her grandfather was literally called Dr. Who, so if Susan's last name truly is "Who", this would imply that Dr. Who is her father's father.