"Theatrythym: Final Fantasy is a new game in the works by Square-Enix that takes the characters, monsters, and locales of the series and sets them in a rythym game. Characters will control a party of chibi-fied characters designed by Monster Octopus. Studio indieszero is developing the game, who’ve partnered with Namco-Bandai and Nintendo in the past for portable and niche games.Nomura is creative producer.
A preface to the game’s plot is also featured on the site. The world of Theatrythym is a time interval called “Rythym” between the realms of Cosmos and Chaos, the two gods featured prominently in Dissidia (but a separate universe regardless). Rythym begets the crystals to fill the world with music, but the forces of Chaos are out to disturb them in some nefarious plot. Thus, the crystals begin to lose their light. They guide warriors of Cosmos, instructing them to create a special kind of music called “Rizupo”.
The time interval between the pillars of the Gods Cosmos and Chaos ─ was called Rhythm.
Rythym produced the crystals through the power of music and the world was filled with the glow of sound.The forces of Harmony and Chaos disturb the Crystals, and the begin to lose their luster.
To restore the light to the crystals, the wave of music called “Rizupo” is needed.
In TRFF, you will be able to form a party of four characters. It was revealed that all the main characters from Final Fantasy I through XIII will be present and accounted for. The game will have “field”, “battle”, and “event” scenes. Characters will level up, receiving experience at the end of a “stage”. There is also an emphasis on collection, as you will be able to collect music and cutscenes. The website notes that Theatrythym is a game that can be considered: “Theatre + Rythym”."
"On the music front, the game will have major songs from the numbered FF games. Specific songs mentioned by Square Enix include Clash on the Big Bridge (Final Fantasy V), One Winged Angel (Final Fantasy VII), At Zanarkand (Final Fantasy X) and The Sunleth Waterscape (Final Fantasy XIII). And, of course, the main FF theme."
^ Thanks to animekittysama