In O. Henry's short story "The Gift of the Magi," no character plays the part of the antagonist. However, if you think about what it was that both Della and Jim struggled against, the only answer is poverty. The husband and wife obviously loved each other very much and were willing to give up their most prized possessions for one another. Della cut off her hair and sold it to buy a watch chain for Jim, and Jim sold his watch to buy beautiful hair combs for Della. If they hadn't been impoverished, each would have easily been able to afford a gift for the other. The fact that, though they were poor, they still found a way to buy meaningful gifts for one another, shows how much they love each other. The antagonist in this story is poverty.