Ever since author Robert Penn Warren definitively said that "The Killers" belonged to Nick Adams and not to Ole Andreson, most people have been sold on that theory. And for good reason. Nick is the only character in the opening scene to have a first and last name. Because he’s the hero of so many other Hemingway tales, any Hemingway readers would immediately recognize him and assume his role as that of protagonist. Warren argues that his conversations with the landlady are further evidence that he’s the star, since they tell us more about Nick than anyone else. The point of the "The Killers," argues Warren, is Nick’s loss of innocence, his discovery of evil in the world. Sounds like a pretty solid case.
But, of course, there are those who disagree about Nick being the protagonist. Every now and then you’re going to bump into someone who thinks Ole is the story’s protagonist, since the whole story is about his murder. Part of the argument is that the story’s real emotional meat comes in when the reader gets to see how tragically defeated Andreson is. We’re the most compassionate towards him, so he’s the hero. Nick’s subsequent conversation with the landlady, then, serves not to tell us about Nick, but to highlight further the irony in Andreson’s character (he’s a lover, not a fighter, he just happens to be a fighter).