 As the first fictional detective , Poe 's Dupin displays many traits which became literary conventions in subsequent fictional detectives , including Sherlock Holmes and Hercule Poirot . Many later characters , for example , follow Poe 's model of the brilliant detective , his personal friend who serves as narrator , and the final revelation being presented before the reasoning that leads up to it . Dupin himself reappears in " The Mystery of Marie Rogêt " and " The Purloined Letter " . 
