Legion contains more minor characters than its predecessor, but its main focus is tighter, concentrating on police lieutenant William Kinderman, a secondary character from The Exorcist. Kinderman is, as Christopher Lehmann-Haupt puts it, a "wondering Jew," equally given to Yiddishisms and philosophical speculation. His name, Lehmann-Haupt points out, means "child- man" in German and "one who is more kind" in English; both fit Kinderman's personality, weighted with empathy for the world's sorrows but eternally questioning and open as a child.

As in The Exorcist, Kinderman's love of "schmaltz" and his sometimes rough or rambling manner conceal a sharp mind and keen perception, both professional and personal. In his theological quest, Kinderman states, "Never mind. Lieutenant Kinderman is on the case." Kinderman's family—wife, daughter, and mother-in-law—are important thematically and to the plot, providing loving support but vulnerable to outside threats.

Winter points out that Legion...