Over time, the ownership of the Oodachi changes. It is shortened from 75cm to a Wakizashi, or a shorter curved blade, of 60cm. It eventually ends up in the Kyougoku family for seven generations. Later, the Kyougoku family decided to move into Marugame Castle, which was said to be haunted by an evil spirit. They believed that a sword from the religious Aoe School would protect them, but the Wakizashi, with no experience with exorcising demons, fails to protect the family from the evil spirit.