John Watson

John Watson was popularly known as the assistance to the detective Sherlock Holmes.

Biography
Watson was known for his fictionalised accounts of the adventures of his friend Sherlock Holmes that were edited by Arthur Conan Doyle, in whose name they were published. Because of this, it was widely believed both contemporaneously and later that Holmes was in fact a fictional character created by Conan Doyle. In 1887, Holmes and Watson assisted the Doctor in battling the Old One Azathoth. (NA: All-Consuming Fire)

Later that year, they travelled to 2010 to attend the wedding of Bernice Summerfield and Jason Kane. (NA: Happy Endings)

Fictional / Meta-Fictional Status
On both occasions of their meeting the Doctor and his associates (and during the various references to said meetings) it is suggested that Sherlock Holmes and John Watson are not in fact their real names, simply the pseudonyms used in the 'stories'.

Information regarding their encounters with Bernice Summerfield and Ace is only provided in subjective form by Bernice herself and Watson, both of whom write diaries of said events. (NA: All-Consuming Fire, Happy Endings)