Indirect characterization is usually presented by the author in five ways (called the STEAL method): Speech, Thoughts, Effect (on other characters), Actions, and Looks.
So, in Wise Blood, we have Flannery O'Connor presenting Hazel Motes as homeless (he has just found his home in Eastrod, Tennessee abandoned), injured, (he is a war veteran with shrapnel in his body), and a suicide (he thinks of jumping off the train). These indirect characteristics parallel his spiritual plight as well. In short, O'Connor presents Hazel Motes as a grotesque (like Frankenstein's Monster).
From the start, O'Connor presents Haze as a man of action, "I'm going to do some things I never have done before." And, as his name suggests, she presents Hazel (or Haze) as spiritually blind. Haze constantly mistakes people: the porter on the train, Asa Hawks for a blind preacher, Sabbath Lily Hawks as the Madonna. The first chapter, origianally titled "The Train," is filled with Hazel's images of death. Hazel's fear of death comes in a series of flashback dreams while he is confined to his coffin-like berth on the train. He sees the burials of his family but refuses to let the coffin lids be shut. Before reaching Taulkingham, his train ride serves as a framing of Hazel's religious confusion.
Later in Taulkingham, O'Connor uses Hazel actions of "fishin' for souls" and the old Essex flivver as a traveling pulpit (Hazel's Church of Christ Without Christ) on wheels to characterize his role as an anti-christ (like the Biblical Saul who persecuted Christians before he was blinded to become the Apostle Paul). Since Haze "ain't got no place to be," he sleeps in the car on nights he is too ashamed to shack up with Leora Watts. Haunted by his grandfather's sexually coveting the woman in the Melsy Carnival coffin, Hazel has nightmares in which he, sleeping in the back of the Essex, is looked upon by the townsfolk, like voyeurs at a sideshow exhibit. These dreams again indirectly characterize Hazel's spiritual confusion and fear.
Through indirect characterization, O'Connor foreshadows Hazel's eventual literal blindness at the end. Like Oedipus, Hazel was warned of his fate, and yet he refused to see Asa Hawks as a charlatan, Enoch Emory as a fool, Lilly Sabbath as a temptress, his Essex flivver as a junker, himself as redeemed but lost, and, most importantly, the Ape-Christ stalking his soul.