Billy Drunnon is a character in The Sinking City. For the document of the same name see the following article: Billy Drunnon (Document)
This article contains spoilers for the Deal with the Devil and Self-Defense case.
Billy Drunnon is a regular at the Seven Oaks Bar, recognisable by his yellow scarf. Reed finds out that Drunnon is the man that found him unconcious near the water after the Nosedive quest, and brought him to the hospital.
Later, Drunnon might be encountered again in the Self-Defense case if Reed chooses to save the kidnapped family of Glenn Byers.