To be honest, Warren is kind of a cipher. He's a combination of generic hot guy and boy next door; he sparks the jealous conflict between Marjorie and Bernice, but otherwise doesn't do a whole lot. Interestingly, he's the one object of desire in this story, which is one of the interesting quirks of this story.
The correct answer is Teller. Because a narrator tells the information you are reading.
What story is it? But I think it fits as a great side character