Short answers, pulled from the story.
The Final Fantasy Trading Card Game is a collectible card game developed by Hobby Japan and published by Square Enix. It features characters from across the Final Fantasy video game series and has been available in English since October 2016.
The Chapter series, which ran from 2011 to 2015, produced 1,898 unique cards across 15 sets. The Opus series had developed 1,700 different cards as of Opus XI, bringing the combined total across both generations to thousands of individual cards.
Each player builds a 50-card deck and tries to deal 7 damage to the opponent. Damage is dealt when an unblocked Forward attacks, sending the top card of the defending player's deck to their Damage Zone. Players generate Crystal Points by dulling Backup cards or discarding cards from hand, then spend those points to play characters and abilities.
The Opus series launched worldwide in October 2016, making the game available in English for the first time. The earlier Chapter series, which ran from February 2011 until 2015, was released only in Japan with all cards printed in Japanese.
The game sold more than 3.5 million booster packs in Japan as of September 2016. Worldwide sales reached more than 5.5 million packs by July 2017, nine months after the global English-language launch.
Square Enix officially runs pre-release tournaments at local game shops, Regional events (called Local Qualifiers in North America), Crystal Cup events themed around Final Fantasy elements, and a World Championship. Previous World Championship locations have included Tokyo, London, and Los Angeles.