Final Fantasy XIII is set on the world of Gran Pulse (often simply called Pulse). Central to the story is Cocoon, a massive artificial sphere that floats above Pulse's surface and is ruled by the Sanctum, a theocratic government. The two worlds are controlled by fal'Cie /fælˈsiː/, beings with godlike power. The Cocoon fal'Cie are responsible for keeping Cocoon floating, as well as providing light and water to the people that live inside. Each fal'Cie handles a specific task. The fal'Cie have the capability of marking the humans that live in Pulse and Cocoon as their servants. These servants, called l'Cie /ləˈsiː/, are branded with a symbol representing either Pulse or Cocoon and are given a "Focus"—a task to complete. If the l'Cie complete their task in time, they are transformed to crystal and according to legend gain eternal life; otherwise they become mindless monsters called Cie'th /siθ/. The l'Cie are not explicitly told their Focus, but are instead given visions that they must interpret.
