The creator of the Kingdom Hearts franchise, Tetsuya Nomura, sought to collaborate with Utada as she previously wrote 'Hikari', alongside his prospects for her to break into foreign and international markets. 'Passion', alongside its English counterpart ' Sanctuary', were used as the national and international theme songs to the Square Enix video game Kingdom Hearts II (2005) the tracks serve as the successors to ' Hikari' and its English counterpart, 'Simple and Clean', which are found on Kingdom Hearts. It premiered on December 14, 2005, in two physical formats and for digital consumption, distributed by EMI Japan and EastWorld. ' Passion' is a song recorded by Japanese-American singer Hikaru Utada, taken as the fourth single from her studio album Ultra Blue (2006).