Sacchan is Akira Fudo's childhood friend who vanishes one night, compelling him to search a playground. There, he finds her merged with the shell of the demon turtle Jinmen alongside other humans, their bodies visibly integrated into its structure after Jinmen possessed or absorbed them. Having transformed into Devilman, Akira recognizes Sacchan and the merged humans are deceased despite their fusion. This understanding drives Devilman to destroy Jinmen.