At the age of 10, he listened to the soundtrack of the anime film Swan Lake, which led him to be influenced by the Russian composer Pyotr Ilyich Tchaikovsky.
[2] Fukusawa worked on the 2003 game Onimusha 2: Samurai's Destiny under lead composer Taro Iwashiro, sampling various traditional Japanese instruments for the soundtrack.
Under the supervision of sound director Masayuki Endou, Fukasawa sought to modernise the music, with instrumental choices influenced by the cultural backgrounds of characters and stages.
[1] Fukasawa composed for Tsukihime -A piece of blue glass moon- with Keita Haga, which released in August 2021.
Fukasawa was approached following the production of Witch on the Holy Night, with Keita presenting him a demo of the main theme, which he then arranged.