John H. Watson was a medical doctor and companion of Sherlock Holmes. He was a veteran of the Second Anglo-Afghan War. (PROSE: A Study in Scarlet) He lived in the same boarding house as Holmes, sharing a suite of rooms on the first floor. He was a regular patron of a brothel staffed by women he believed to be "clean," and of good breeding. It was his medical opinion that a man required regular sexual release for the sake of his health. (PROSE: Erasing Sherlock)
The first case Holmes and Watson investigated together was a double murder carried out by Jefferson Hope. Following this, Watson began recording their investigations in his diaries. (PROSE: A Study in Scarlet)
Watson was kidnapped by minions of Thomas Peerson Corkle, who brought him to Java in the shadow of Mount Krakatoa just prior to its famous eruption in order to lure Sherlock Holmes and Gillian Rose Petra there. Corkle promised to move Watson to safety in exchange for Gillian's cooperation. (PROSE: Erasing Sherlock)
Watson did manage to survive, as nine years later (in 1890) he was back in London, now married and expecting a child. Watson and Holmes were drifting apart; they hadn't spoken in five months. He complained to Holmes that he was being followed by a mysterious veiled woman. (PROSE: Erasing Sherlock Prologue)
In 1916, Watson was a Colonel. When Count Dracula made overtures of peace during World War I, Watson was his contact. He orchestrated a plan by which Dracula was trapped underwater in a submarine. (PROSE: The Found World)