Because of the way he is characterized, Arnold Friend symbolizes evil.
Even Arnold Friend's name reflects his evil intentions. By removing the r from both names, we are left with "An Old Fiend." When he arrives at Connie's house, Arnold Friend gives the horn "four short taps, as if this were a signal Connie knew." Careful readers might recognize the allusion to "Taps," a song often played at funerals.
Arnold Friend looks as if he does "hard work," and his nose is "hawklike." When Friend takes off his sunglasses, Connie notices how pale his skin is, and later she believes that his entire face is a "mask." He keeps wobbling in his boots, and it seems as though "his feet did not go all the way down." Readers can infer that perhaps Arnold Friend does not have human feet at all, but instead has hooves, which are often associated with the devil.
The various aspects of Arnold Friend's physical description reflect that he could be the devil incarnate. He seems to possess an unnatural ability to predict human behavior and to have insight into events he is not present to witness:
"If my father comes and sees you—"
"He ain't coming. He's at a barbecue."
"How do you know that?"
"Aunt Tillie's. Right now they're uh—they're drinking. Sitting around," he said vaguely, squinting as if he were staring all the way to town and over to Aunt Tillie's back yard. Then the vision seemed to get clear and he nodded energetically. "Yeah. Sitting around. There's your sister in a blue dress, huh?"
Arnold Friend convinces Connie that she must comply with his wishes in order to spare her family; she agrees to his terms, knowing that she must surrender both her sexuality and her life in order to keep her family safe. Connie feels that she must accept her fate and that she is powerless against the desires of Arnold Friend.
The characterization of Arnold Friend, his supernatural knowledge, and his horrific plans for Connie combine to create a chilling character who symbolizes evil.