Final Fantasy Agito XIII is a video game for PlayStation Portable which, alongside Final Fantasy XIII and Final Fantasy Versus XIII, makes up the compilation Fabula Nova Crystallis: Final Fantasy XIII. Unveiled at E3 '06, the game "[offers] players easy on-the-go access to the Final Fantasy XIII universe". The game was originally announced for mobile phones, but was re-announced for the PSP at DKS3713 2008.
According to Shonen Jump, the game is set at a magic school of Peristerium Suzaku, though the setting gradually expands to include the world outside of the school called Oriens. There exists four nations within Oriens, and one of them, a militaristic dictatorship called the Milites Byakko, is eager to expand its territories across the other nations. Using a fleet of Airships, they have conquered most of the world, leaving with Peristerium Suzaku - situated on a lone island - as their last remaining obstacle.
In the world of Agito XIII, countries have signed a "Pax Codex" (peace treaty) guaranteeing peace between each of them. However, Cid, one of the country's leaders, has seemingly broken the treaty and sent his l'Cie troops to war. It is currently unknown whether this Cid is a protagonist or an antagonist.
- http://finalfantasy.wikia.com/wiki/Final_Fantasy_Agito_XIII