After studying it in depth in order to accurately portray a priest in this film, Japanese-American actor Cary-Hiroyuki Tagawa decided to convert to the Russian Orthodox faith. He was baptized on November 13, 2015, just 2 weeks before the release of the film. As a result of his conversion, he ultimately chose to become a Russian citizen.
Ivan Okhlobystin, who wrote and produced the film, and played one of the major villains, is a Russian Orthodox priest.