Crystal Defenders is a series of turn-based strategy games that use units from Final Fantasy Tactics A2. The first iteration, Crystal Guardians, was released for mobile phones in early 2008 only in Japan. The second, eponymous iteration was released through various online video game delivery services starting in 2008. Crystal Defenders: Vanguard Storm, featuring a new gameplay system, was released for the iPhone in May 2009.
Read more about this topic: Final Fantasy Tactics A2: Grimoire Of The Rift