"In Christopher Nolan’s The Dark Knight, The Joker, played by the late Heath Ledger, is a charismatic and insane villain, who some fans believe was a veteran of the wars in Iraq or Afghanistan suffering from Post-Traumatic Stress Disorder. The theory comes from a story The Joker tells Harvey Dent in the second half of the film about a truckload of soldiers being blown up. This might also explain the character's disdain for the establishment and his proficiency with explosives, a bazooka, and automatic assault rifles."