CASPER — Father Chad Ripperger fits a familiar Western mold — up to a point. He fly-fishes. He shoots powerful handguns. He enjoys aged Scotch and expensive cigars. But the familiarity ends there. Ripperger is one of the Roman Catholic Church’s most experienced and well-known exorcists. A native of Casper, Wyoming, he is a founding priest of the Society of the Most Sorrowful Mother, the first Catholic society chartered exclusively for the work of exorcism under the authority of the Archdiocese of Denver. Within what the Church calls “spiritual warfare,” Ripperger’s outfit is something like a SEAL Team 6 —...