The Echoing Oni

Asumu Adachi and his mother went to Yaku Island for a family reunion. During the boat ride to the island, Asumu meets a man named Hibiki, who has just saved a child from going overboard. On Yaku Island, people are disappearing in the forests and Hibiki goes in to investigate. In the forest, Asumu and his cousin meet Hibiki and also run into a pair of demons known as Douji and Hime of the Makamou. Hibiki goes to fight the Makamou and transforms into an armored figure called an Oni. When cornering one of the Makamou, Hibiki is seen by Asumu.