Scribes Brian Klugman and Lee Sternthal, who were credited with a "story by" alongside Edward Kitsis and Adam Horowitz on Tron: Legacy, have been tapped to write the screenplay for Warner Bros.’ adaptation of Rex Mundi. Produced by Johnny Depp and his Infinitum Nihil banner, the film is based on the Dark Horse comic that centers on the quest for the Holy Grail in an alternative 1933 Europe where the Protestant Reformation was crushed by Catholocism and magic exists.

Heat Vision reports that Depp is producing alongside Infinitum Nihil’s Christi Dembrowski, Alan and Peter Riche. Rex Mundi tells the story of the quest for the Holy Grail by way of a murder mystery, with the protagonist (a pathologist) searching for the truth behind the death of the priest who cared for him as an orphan child.