The blood creates striking tableaus — drenching the dress Evelyn Herlitzius wears as she sings the role of Kundry, a wild woman in the thrall of an evil sorcerer; and helping the audience visualize the spiritual quest taken by Parsifal (the tenor Klaus Florian Vogt). And it fits squarely into Mr. Girard’s conception of the opera.

“We’re talking about life, Christ, Amfortas’s wound, sexuality, all of those things,” he said. “Blood became the connector.”