 The monsters drew inspiration from creatures of H. P. Lovecraft's Cthulhu Mythos, putting them in contrast with the enemies of anime and movies of the time which were described by Machida as generic animal or prehistoric designs.The music of "Shadow Hearts" was composed by Yoshitaka Hirota, with additional contributions by Masaharu Iwata, Yasunori Mitsuda and Ryo Fukuda.Hirota wanted emulate Hiroki Kikuta's music for "Koudelka", creating a score that was "beautiful yet destructive".