Toriyama also wished for the music to have "a more edgy sound" and more vocal pieces, so that it would sound "unlike the typical "Final Fantasy" title". The music incorporates a wide variety of styles, from orchestral and electronic to rap, hip-hop, jazz funk, and metal. Prior to the game Hamauzu was known for working on orchestral pieces, Mizuta for instrumental pieces, and Suzuki for electronic pieces, and as a result all three composers attempted to write music that did not fit their general style to avoid only writing music similar to what they had produced before. They also worked with each other to blend their styles together, so that shifts between composers in the soundtrack would not be jarring. While the music is not intended to be reminiscent of "Final Fantasy XIII"'s music, pieces set in scenes involving places or characters from the prequel use motifs and pieces of music used in that game for those places or characters. Mizuta's favorite song from the soundtrack that he wrote is "Caius's Theme", which he rewrote four times over the course of a month. Suzuki's favorite is "Historia Crux", which he wrote as several tunes mixing into one as a metaphor for time travel in the game, and Hamauzu's is "Knight of the Goddess", the battle theme for the game, which he attempted to make the equal of "Blinded by Light", the battle theme of the prequel, which he felt was very well received. The first album of music from the game which Square Enix released is "Final Fantasy XIII-2 Original Soundtrack". The album contains all of the musical tracks from the game, and was composed and produced by Masashi Hamauzu, Naoshi Mizuta, and Mitsuto Suzuki. Some of the tracks were arranged by Ryo Yamazaki, Yoshitaka Suzuki, Kengo Tokusashi, Shootie HG, and Sachiko Miyano, and a few songs were arrangements of previous "Final Fantasy" composer Nobuo Uematsu's chocobo theme. Multiple artists made lyrical contributions, including Shootie HG, Origa, and Aimee Blackschleger. The soundtrack spans four discs and 79 tracks, covering a duration of 5:01:22. It was released by Square Enix on December 14, 2011 in Japan and on February 2, 2012 in North America as a part of the limited edition of the game, bearing the catalog numbers SQEX-10296~9.