Saul has several major themes in his horror fiction; children as victims, and sometimes perpetrators, of evil; technology used for horrific ends; and occult occurrences (is it something external or internal that causes the horrible things to happen to his characters?). While Saul's earlier work has been noted for its extremely gruesome quality, in his later writing Saul is trying to restrain that aspect of his fiction. Often his plots revolve around hidden, secret evil that is discovered by an innocent person, who must then battle against seemingly impossible odds to defeat the demon.