|Gillian and John
As Real Beings
John and Gillian lived in 1960s England. Their grandfather was Doctor Who (the Doctor was constantly mistakenly called "Dr. Who" in the strip). They knew very little about their grandpa. However, they accidentally found and got inside his TARDIS (the Doctor's space-time travelling machine). Doctor Who decided to take them on his adventures. They fought such as enemies as the Kleptons, the Trods (who I did a post on), the Pied Piper and the evil Captain Anastas Thrax. The duo got separated from Doctor Who. However, they reunited with the second Doctor. Due the Doctor's time travelling, it seemed like a short time passed from duo's perceptive. They continued with their adventures. However this time, they fought actual villains from the show such as the Cybermen and Daleks. Eventually, the Doctor Who left them on the planet Zebadee where they went to college. John became a professor and took the name "John Who".
As Fictional Beings
Due to continuity errors in the original comic strip, it was claimed the original comic strip never happened. In the Doctor Who mythos, the Land of Fiction is a pocket universe full of fictional characters. The Seventh Doctor visited this realm and encountered two beings named "John" and "Gillian". They believed they were his grandchildren and tried to refresh his memory (even mentioning the Trods and Kleptons). However, the Doctor claimed that he did none of that. So, "Doctor Who" may just be alternate version of the Doctor that exists in the Land of Fiction. The Eight Doctor is shown to have pleasant dreams of a "less complicated" universe where "people never die", "promises are never broken" and "villains are naught, not evil". In these dreams, he is seen travelling with John and Gillian.