The three sisters are three older women who refer to themselves as aunts, although it’s unclear whose aunts they are. They arrive in the novel after Rachel and Lucy’s baby sister dies, appearing as visitors at the girls’ house along with other mourners. The three sisters are unnamed and referred to by their physical characteristics, and they are also never confirmed to be related in any way to anyone on Mango Street, which heightens the sense of mystery and mythology around them.
The three sisters seem particularly interested in Esperanza and entertain themselves by predicting tomorrow’s weather and reading Esperanza’s palms. At first, they seem to have the normal wisdom and foretelling abilities of experienced older women, but later their prophetic visions seem to be heightened beyond the realm of realism. One of the aunts guesses Esperanza’s unspoken wish – to escape Mango Street – and warns her that she can’t abandon Mango Street fully. The aunt wishes for Esperanza to remember her roots and come back to help those who couldn’t escape on their own. Esperanza doesn’t completely understand the aunt’s advice, but it’s clear that the aunt has recognized an ability and potential in Esperanza that Esperanza herself has not yet come to terms with. After the three sisters tell Esperanza’s fortune, she never sees them again, intensifying the sense that they arrived at Rachel and Lucy’s house solely to impart their wisdom to Esperanza. Realistically, they might simply be distant relatives in a large Latin American family, but because of their mysterious origins and powers, the three sisters function in a way that is almost supernatural or magical. In fact, the aunts are reminiscent of the three Fates in Greek mythology, who are three sisters that determine the destinies of humans via spinning, measuring, and cutting each person’s thread of life.