The narrator provides essential exposition throughout the two-episode OVA, delivering contextual information about the setting and unfolding events. This voice establishes the backdrop of war-torn feudal Japan and introduces the emergence of bloodshed-fueled yōma demons across its battlefields. The narration specifically frames the central conflict, setting up the protagonist's pursuit of his transformed former comrade. It contributes to the story's dark and oppressive atmosphere while covering significant plot developments across both episodes. The narrator's delivery remains consistently neutral and informative throughout, with no depicted personal backstory, character development, or direct involvement in events. This narration includes introducing the prologue song "Yōma Kazoe Uta" and the epilogue theme "Ashita e no Prologue".