The Wagnerite’s Holy of Holies inaugurates a new season with the Master’s hypnotic chant of love and death. The production is by the 40-something Icelandic actor, playwright, and director Thorleifur Örn Arnarsson, a newcomer to the festival with no known strikes against him; for good or ill, this assignment will redefine his career. Semyon Bychkov, who found favor here conducting Parsifal in 2018 and 2019, returns to lead the local favorites Andreas Schager and Camilla Nylund as the adulterous lovers, Günther Gröissböck as the king they betray, and Ekaterina Gubanova as the busybody who pours a love potion when her mistress demands poison. As a recent recruit to Isolde and Wagner’s other supreme challenge for soprano, the “Ring” cycle’s Valkyrie Brünnhilde, Nylund has our special attention. Right now, the opera world is chomping at the bit to hear these roles in the voice of the Norwegian phenomenon Lise Davidsen, who is still biding her time. Of Davidsen, fans are anticipating clarion projection recalling the incomparable Birgit Nilsson, and indeed, Isolde’s and Brünnhilde’s music incorporates war whoops and other outbursts for which only a sword’s edge of flaming steel will suffice. Nylund’s gentler, softer-grained instrument shines brightest in the heroines’ more vulnerable, conventionally “feminine” moments, which are no less of the essence. —Matthew Gurewitsch