Who is John Flory from Burmese Days and what is their importance?

John Flory, born circa 1890, is addressed in the native patois as "Mr. Porley". At the time of the novel's opening sequences, around 1925, he is about thirty-five years old, of average height, and has black, stiff hair. He wears a mustache and has sallow, nearly yellow skin. His most distinguishing feature, however, is a grotesque and large birthmark which covers most of the left half of his face, running in a large crescent from his eye to his chin.