Susan Ellen Who is the Human Granddaughter of the time traveling adventurer and scientist mysteriously known only as Dr. Who. It was with young Susan's aid that Earth and a large portion of the known galaxy and history was saved from the ruthless mechanized alien war force known as the Daleks of Skaro not once but 3 separate occasions from the 20th to late-mid 21st Centuries.
After her grandfathers passing by the late 20th Century complete control and passing of the TARDIS was given to Susan mainly due to her unusually high shared intellect and unquenchable thirst for new and radical scientific knowledge with her grandfather. Due to her extensive use of the TARDIS many alien races had given her the moniker of "The Doctor" mainly because they had believed that she and her grandfather were one and the same. So after a while she had accepted this name and afterward only her most closest family and friends knew her true name.
It was also due to her intervention with the society of planet Skaro that she was able to unite the Kaled and Thal races leading to a new and (so far) unparalleled era of peace now known as the New Skaro Era which had existed for several 100 years until civil war broke out which involved the 4th Doctor and later the 5th and 6th Doctors.
Susan Who was born the youngest of 2 girls on May 10, 1958 with a older sister Barbra in central London, England
From an early age Susan Who had shown a highly advanced genius intellect that had no seeming equal. She had the ability to read at only 6 months and could complete complex mathematical equations at 2 years old. Susans parents realized that their prodigy child was far too smart for even the best private and gifted schools the country had to offer so at only 3 years she was sent too be tutored by her only living grandparent Dr. Who for extensive home schooling.
However at the age of 5 Susan's fate was changed forever when her parents who were international investment bankers had died in a tragic plane crash near South Africa. Leaving the 2 girls orphaned with only their grandfather their last living relative to care for them.
Time Travel and Skaro Interaction
For many years Susan knew and in small part helped with grandfathers creation of his greatest invention ever, The Tardis a interdimensional spacial craft that traveled via a temporal/spacial displacement field that (only in theory at first) could travel to nearly any point in the known universe.
Susans 1st trip (albeit accidentally) in the TARDIS was in 1966 after Barbra's boyfriend Ian had accidentally tripped over the capsules main temporal throttle which sent them to the distant planet of Skaro a ruined post apocalyptic world which survived massive nuclear war between its 2 main sentient species the Kaleds and Thals.