Tougen Anki: Nikko Kegon no Taki-hen

Shiki Ichinose and his companions head to Nikko after an impossible phenomenon appears: Kegon Falls has stopped flowing, and a massive research facility has been built nearby away from public view. What happens inside is no ordinary research, but terrifying experimentation connected to the continuing conflict between the Oni bloodline and the Momotaro Agency.

Part-time instructor Hagure Nekosaki joins the mission, while Yu Innami emerges within the complicated case. The closer Shiki gets to the facility, the clearer it becomes that the silent waterfall is only the visible edge of a larger danger, and that people inside may be paying the price for a war inherited long before they were born.