The image of the ninja as a silent assassin in head-to-toe black is largely a later invention. Historical evidence suggests that ninja, or shinobi, were mainly spies and infiltrators who gathered information, sabotaged defences and moved unseen behind enemy lines in feudal Japan. When they did need to disguise themselves for combat, they typically wore dark brown clothing, while in peacetime they blended in as ordinary workers in dark indigo garments like those worn by farmers. The fully black outfit became popular through Japanese theatre of the Edo period, where dark costumes helped stage hands and performers become invisible on stage. Those theatrical conventions were then absorbed into films, comics and games, which turned them into the iconic image most people know today.

In 1909 D. W. Griffith made a 14-minute film about a speculator who corners the wheat market and doubles the price of bread. A farmer sows his field while a 'Wheat King' gambles in the Chicago wheat pit; bakers raise the loaf from five cents to ten and the poor line up for bread. Griffith cut back and forth between the farm, the feast and the breadline, a technique called parallel editing, so audiences saw both ends of the economy at once. The film drew on Frank Norris's stories and on a real scheme: months earlier Chicago financier James Patten had cornered wheat, sent bread prices up and made about $5 million, roughly $185 million today.