Short answers, pulled from the story.
Dissidia Final Fantasy was released in Japan on the 18th of December 2008. The North American launch followed on the 25th of August 2009, and the game arrived in Europe and Australia in September of that same year.
Tetsuya Nomura created Dissidia Final Fantasy as a creative producer who initially envisioned a crossover between Disney characters and Kingdom Hearts heroes before shifting focus to the Final Fantasy cast. The game was directed by Takeshi Arakawa and developed over three years to blend role-playing depth with fighting game speed.
Bravery Points, or BRV, function as a unique economic system where players steal resources from opponents to execute HP attacks that deal damage equal to their current Bravery amount. If a character's BRV drops below zero, they enter Break mode where they cannot deal damage but take critical damage from any attack.
As of August 2009, Dissidia Final Fantasy had sold 910,000 copies in Japan, making it the fourth best-selling game for the PlayStation Portable in that region. It was also the 12th best-selling game in Japan in 2008 with 660,262 copies sold.
Takeharu Ishimoto composed the soundtrack for Dissidia Final Fantasy, blending remixes of Nobuo Uematsu's original music with new compositions. The main theme, The Messenger, was performed by the band Your Favorite Enemies, who also contributed the tracks Cosmos and Chaos - Last Battle 1.
The international version of the game, named Dissidia Final Fantasy: Universal Tuning, was released in Japan on the 1st of November 2009. This version is a direct port of the North American edition and retains all extra features added to the Western release.