Why is Angel the antagonist in Buried Onions?

In Buried Onions, author Gary Soto sets up the ironically named Angel as the antagonist to the novel's protagonist, Eddie. Referred to as a "gangster" by Eddie, Angel lives in the neighborhood and was a friend of Eddie's cousin Jesús who was stabbed to death at a local nightclub. Both Angel and Jesús's mother want Eddie to go after the killer. When Eddie meets Angel at Holmes Playground in chapter one, he is obviously quite leery of Angel. He calls Angel "sneaky" and "vicious." Later in the novel, the two stage a bitter fight, which carries over through the end of the book.
Eddie has two conflicts with Angel. First, he views Angel as everything he doesn't want to become. Angel runs with a gang, breaks into people's houses, and is usually drunk or stoned. Eddie is searching for something else, a way to get out of his dead-end ghetto in Fresno. Second, Eddie comes to believe that it was actually Angel who killed Jesús, rather than the guy with the yellow shoes who is pegged by Angel as the killer. In the end, Eddie joins the navy and leaves Fresno, primarily because he seeks to avoid another violent confrontation with Angel.