Her music, based around themes of 'friendship' and 'filial bonds', incorporates multiple musical genres, such as orchestral, bossa nova, and American blues. Shimomura was brought on board the project in 2006, when it was a spin-off title called Final Fantasy Versus XIII, and stayed in her role during the game's ten-year development cycle. Having previously worked on the Kingdom Hearts series, among various other titles, Final Fantasy XV was her first project for the series. The music for the video game Final Fantasy XV, developed and published by Square Enix as the fifteenth mainline entry in the Final Fantasy series, was composed primarily by Yoko Shimomura.
