In a chilling OVA adaptation of Jirou Tsunoda's manga, 'Hyakutarou behind' follows Ichitarou Ushiro as he grapples with eerie occurrences alongside his protective spirit, Hyakutarou. The two-episode series delves into the mysteries of 'Kokkuri Satsujin Jiken' and 'Yuutai Ridatsu', showcasing a blend of horror and supernatural elements in Ichitarou's terrifying journey.