The game's theme song, "Zero", was composed and performed by Japanese rock band Bump of Chicken. The band, which was a big fan of the "Final Fantasy" series, was contacted by Square Enix to compose and perform the song and agreed readily. It was brought in after the platform move onto the PSP, but while the game was still titled "Agito XIII". While looking for inspiration, the band was able to see in-development screenshots of the game, samples of the script, and character illustrations. The band was mostly given a free hand while composing the song. Its one guideline was provided by Tabata, who suggested the theme song for "Centuries of Picture", "Is Paris Burning?" by Takeshi Kako, as a source of inspiration. Multiple versions of "Zero" were composed for use in different areas of the game. At the request of band leader Motoo Fujiwara, Amano's logo artwork was used for the cover of the single's limited edition.