official website of film production company Legendary Pictures has recently been updated to reflect a Diablo movie entering development alongside the previously announced World of Warcraft film. As far as game-to-film adaptations go, Blizzard's demonic role-player probably represents one of the better properties to mine, certainly ranking above The Sims and Dead or Alive. Examining the group's lineup of completed films, which includes Batman Begins and 300, vaguely instills some confidence in this adaptation, but we think you'll find the hands of movie executives usually have a way of wringing that out of you.
No other information about the Diablo film has been disclosed, though it seems a fair guess that it'll have the eponymous villain attempting to wreck the world, only to be foiled by a floating arrow constantly jabbing at his head. Blizzard was unavailable for comment at the time of writing -- presumably off shoving large jewels into their skulls.
[Update: The Diablo listing has since been removed from the Legendary Pictures website.]