The CW has announced that Australian actor and former rugby player Matthew Nable, who American audiences may know best as Boss Johns from the movie Riddick, will play Ra's al Ghul in the upcoming third season of Arrow, starting with the fourth episode, "The Magician."
Changing the racial identity of characters has become a contentious issue amongst fans of superhero comics and their adaptations in other media. The awful practices of casting white actors to play people of color, or of turning previously non-white characters into white characters, is all too common in movie adaptations of books, cartoons, TV shows, or even real life stories -- but rather surprisingly, superhero comics and their adaptations have mostly avoided this problem.
In comics, the controversy takes a different direction. Several white characters have become non-white, mostly in movies, and sometimes in reboots. Michael B. Jordan as Johnny Storm in the new Fantastic Four; Helena Bertinelli aka the Huntress in the New 52; Nick Fury in the Ultimate Comics line and on screen. These are changes that agitate some readers -- but realistically, the changes don't go far enough. Superhero comics have a cultural bias towards white characters that has everything to do with their institutional history and nothing to do with what makes sense to the stories.