Though largely a believer in non-violent conflict resolution, they were, when absolutely necessary, a great warrior. Indeed, some civilizations in the universe (e.g. the denizens of the Gamma Forests) translated the word doctor as warrior, (TV: A Good Man Goes to War) whilst others saw the Doctor as a compassionate benefactor, worthy of their admiration and compassion. (TV: Last of the Time Lords, The Wedding of River Song)
Although he had saved untold numbers on his travels, he was thought to have caused the deaths of billions at the conclusion to the Last Great Time War. (TV: Dalek) Though most of the Daleks were killed in the crossfire, Gallifrey — disappearing, rather than being burned — was hidden thanks to the efforts of "all thirteen" of his incarnations, the first eleven of which retained no memory of the event. (TV: The Day of the Doctor) For his actions, the Time Lords granted him a new cycle of regenerations, allowing him to live on after using up all available regenerations in his first cycle. (TV: The Time of the Doctor)
From the latter years of his first incarnation onward, the Doctor had a pronounced affinity for Earth and the human race. After departing Gallifrey, he voluntarily chose to spend time on the planet, (TV: An Unearthly Child, AUDIO: Summer, The Haunting of Thomas Brewster) choosing it as the place of his exile during most of his third incarnation, (TV: Spearhead from Space - The Three Doctors) and even owning property in Kent (COMIC: Fellow Travelers, PROSE: Verdigris, Warlock, Warchild, The Dying Days, Mad Dogs and Englishmen) and New York City. (PROSE: The Forgotten Army) He favored Great Britain as a frequently visited location, taking most of his companions from there. (TV: An Unearthly Child, Spearhead from Space, The Time Monster, Rose, Smith and Jones, Partners in Crime, etc.) Even before the disappearance of Gallifrey, the Doctor spent much more time on Earth than on his homeworld.
The Doctor's personal history was constantly changing and contradicting itself. (PROSE: Unnatural History)
Played by: The Doctor has been played by many people. These include William Hartnell, Patrick Troughton, Jon Pertwee, Tom Baker, Peter Davison, Colin Baker, Sylvester McCoy, Paul McGaan, Christopher Eccelston, David Tennant, Matt Smith, John Hurt, and Peter Capaldi.
The Protectors of the Multi-Universe
The Doctor is a friend and guardian of David, Abigail and Olivia. He has also been like a father to Abigail.
The Chaotic Wars
Jessie, James and Meowth stumbled upon part of the TARDIS and found a message from the Doctor. He had picked up on a strange reading which lead him to that dimension. Unfortunately, something there lead him to his demise.
The Doctor, being a Time Lord, has had many faces, with a total of thirteen (technically fifteen) at this point. Only a few have been involved in the many struggles of the Multi-Universe, however.
The Ninth Doctor
The Tenth Doctor
It should be noted that, though he called himself the Tenth, he was really the Eleventh and the Twelfth, on account of ignoring the War Doctor and creating a Meta-Crisis to keep his face.
This Doctor may have been a bit vain, due to his extreme reluctance to regenerate (he insisted that it would be just like dying) while almost all other Doctors treated the process of regeneration like no big deal.
The Eleventh DoctorIt should be noted that, though he called himself the Eleventh, he was in reality the Thirteenth Doctor.
This Doctor is a much more quirky, childish, and upbeat character compared to those that came before and after him. He also expressed much more compassion than other recent Doctors.
The Twelfth DoctorAppearing externally older than his past few incarnations, this Doctor is rude, abrasive, and proud. He seems to have lost much respect for almost everything in the universe. Menslady125, however, is very fond of him.
The Thirteenth DoctorThe Thirteenth Doctor is the latest incarnation, succeeding the Twelfth Doctor. She is the first Doctor to be female.
Powers and abilities
Regeneration 1 - allows the avoidance of death by taking on a new physical appearance
Regeneration 2 - allows the regeneration of a severed body part
Sonic Wave - sends out a wave of energy from the Sonic Screwdriver that can not only break tough locks, but damage an opponent
Sonic Scream - a stronger version of Sonic Wave that causes massive damage to an opponent
Disney Magic - summons the magic of Disney. The Doctor has also found a way to channel it through his Sonic Screwdriver.