David Campbell, also called David Cameron, (PROSE: Doctor Who and the Crusaders, A Brief History of Time Lords) was a freedom fighter on Earth during the Daleks' 22nd century invasion and occupation of Earth. He married the Doctor's granddaughter Susan Foreman and was eventually killed by the Master, who did not realise he had murdered one of the Doctor's in-laws, not having recognized Susan.
They helped him stop the total destruction of the city and helped destroy the Dalek forces. David and Susan quickly fell in love with each other. She stayed with him to help restore the Earth. Shortly after Susan's departure from the TARDIS, they were married. (TV: The Dalek Invasion of Earth)
David and Susan spent at least thirty years together. (PROSE: Legacy of the Daleks) Although according to one account, David did father a child of Susan, Alex, who died shortly after his birth, (AUDIO: An Earthly Child) another account stated that despite trying their best, they were unable to conceive children due to the hazardous nature of cross-species reproduction. Still wishing to raise a family, in part due to the social stigma of a childless couple in the heavily depopulated post-Dalek world, they adopted three orphaned children, whom they named David Campbell Junior, Ian Campbell and Barbara Campbell, after Susan's husband and former teachers. David was heralded as a great hero for his efforts during the invasion.
By the time that David was fifty-four, he had grown visibly older (and portlier), while Susan still looked eighteen due to her Time Lord physiology. She managed to make herself look older to keep up appearances before their human friends, David and Susan both being rather in view in the elite that arose out of the freedom fighters. However, the discrepancy in their lifespans still put a strain on David and Susan's relationship; although they both still loved each other, Susan found it almost too much to bear to see her beloved decaying before her eyes, and David, for his part, was heartbroken that his being a human put his wife through such hardships. Shortly before his untimely death, David was giving thought to divorcing her for her own good, even if he didn't think he could bring himself to do such a thing.
Shortly after the Doctor (now in his eighth body) was reunited with them both, David was killed by the Master, throwing himself in front of the Doctor to save his grandfather-in-law when an irate Master attempted to shoot his old archenemy. The Master then took Susan as a hostage and absconded with her to the planet Tersurus, where she managed to severely wound the Renegade and escape. (PROSE: Legacy of the Daleks)