The characters of Theatrhythm Final Fantasy -- both ally and enemy -- come from across all 13 Final Fantasies. Yet instead of mixing and matching art styles, Square Enix hired the Japanese design studio Monster Octopus to recreate all these Final Fantasy characters in their own cute, doll-like style.
This is far from the only time Monster Octopus' art style has been used in a Square Enix game. The Japan-only phone game, Kingdom Hearts Mobile first used these sprites across its collection of minigames back in 2008. The DS remake of a different phone game, Kingdom Hearts Re:coded, allowed players to make their own avatars in this style as well. Only a few weeks before Theatrhythm's release, Square Enix launched the Monster Octopus' designed Final Fantasy Brigade on phones across Japan.
Over the last few years the art style has become popular enough to warrant more than a little merchandise. An ever-growing collection of phone straps are available on the Japanese Square Enix Store website along with other choice items.
Now if only they would make a phone strap of everyone's favourite giant purple octopus.