The question contains minor spoilers for Where Are You Going, Where Have You Been, by Joyce Carol Oates.
In this short story, a teenage girl is menaced by two mysterious characters who seem to know a great deal more about her than they should. You can read the story online.
The precise nature of these two characters is never revealed, but there are pretty significant clues as to who the more talkative of the two, Arnold Friend, is. The other is named only as "Ellie" and says little, other than to back up Arnold's more persuasive style with the threat of physical violence. Ellie spends much of his time listening to pop music on a transistor radio.
Ellie's function in the narrative is fairly clear to me, but I'm puzzled as to the nature of the character. If we imagine Arnold Friend is what he is implied to be, then it seems unlikely he'd be going around with a friend. And the name "Ellie" is puzzling: it's a female name, but the character is clearly stated to be male. It's also noteworthy that he's supposedly older than Arnold.
Apparently, literary critic Joan Easterly has suggested Ellie is a parody of the Greek god of mercy, Elios. That would offer a reason why he's older than Arnold but other aspects of this feel like a stretch: the story is not a parody, Ellie is certainly not merciful and it doesn't explain his silence, or the radio, or the gender-fluid name.
Are there any other theories as to who Ellie represents, or any clues from the author we can go on?