Antonio's uncles—María's brothers—pop in and out throughout the novel to both remind Antonio of his heritage as a Luna farmer, and also just to be nice to the kind. They're kind, gentle, and handy in a pinch, as when Pedro saves Antonio from Tenorio, the Big Bad.
Chávez, Jasón's papa, is a bit of a hot head. He's the guy who leads the mob to go ice Lupito, who killed his brother during a particularly violent episode of what we can only assume is Post Traumatic Stress Disorder. In any case, we don't harbor much love for Chávez (although we do harbor some sympathy), because he's also a bit close-minded, having forbidden his son to hang out with the local Indian because he thinks he's a bad influence.
This guy invokes the wrath of Tenorio when he stands up to him on Ultima's behalf. That earns him a curse on his home, which Ultima lifts with her mad magic skills.
The local Catholic priest teaches Antonio and all the other kiddos the Catechism, and that's about it. He's conservative, strict, and if you're looking for the book's stand-in for the Catholic church, look no further.
Rosie runs the brothel in town, and probably knows Andrew pretty well as a frequent customer.
The patriarch of the Luna clan is Antonio's grandpa and María's papa. Think of him as an isolationist who prefers not to get involved in the affairs of others, whether they're mere shenanigans or full-fledged blood feuds.
Miss Maestas is the teacher we all wish we had. She sees Antonio's smart right off the bat, and treats him well, even arranging for him to skip a grade because he's just that smart. That lands him in Miss Violet's class, and she's not nearly as awesome.