What is the author's style in Mammon and the Archer by O. Henry?

Although it may not appear so at first, "Mammon and the Archer" is ultimately a first-person narrative. The story begins in the third person, with the unnamed narrator giving details about Anthony Rockwall, his neighbor, and others. In third-person narratives, the narrator is not part of the story and is merely there to guide the reader through the characters' story. However, near the end of this story, right before the surprise ending, O. Henry talks directly to the audience, saying: "The story should end here. I wish it would as heartily as you who read it wish it did. But we must go to the bottom of the well for truth." With this statement, O. Henry draws attention to himself, and he becomes one of the characters.