Short answers, pulled from the story.
Final Fantasy XIII-2 is a 2011 role-playing game in which Serah Farron and Noel Kreiss travel through time to find Lightning, who has disappeared after the events of Final Fantasy XIII. The story features a heavy time travel element, paradoxes scattered across multiple historical periods, and an antagonist named Caius Ballad who seeks to destroy all time.
Final Fantasy XIII-2 was released on the 15th of December 2011 in Japan, and in 2012 in North America and PAL regions. A Windows port followed in 2014.
Final Fantasy XIII-2 sold 524,000 copies in its first week in Japan and reached 3.1 million copies worldwide by January 2013. An additional roughly 400,000 copies were registered on Steam by 2017, according to Steam Spy.
The soundtrack was composed by Masashi Hamauzu, Naoshi Mizuta, and Mitsuto Suzuki. Mizuta wrote nearly half of the tracks, while Hamauzu and Suzuki each wrote roughly a quarter. The original soundtrack album reached number 13 on the Japanese Oricon charts.
Final Fantasy XIII-2 adds a monster capture system allowing players to recruit around 150 monster types for use as a third party member in battle. The Paradigm system returns with six roles, and the ATB bar can expand from three to six slots over the course of the game.
Yes. Lightning Returns: Final Fantasy XIII was announced after XIII-2 shipped with a "To be continued" ending. It was released in Japan in 2013 and worldwide in 2014, and serves as the conclusion to the story of the main Final Fantasy XIII character, Lightning.