Karasumori (烏森, Crow Forest) is the land that both the Sumimura and Yukimura families have defended for many generations, named for the lord whose soul resides beneath it. This task was entrusted to them by Tokimori Hazama, founder of the Hazama-Ryu Kekkaijutsu, the once mighty Kekkaishi who passed his teachings onto them. However, the mystery of Karasumori, the Ayakashi who constantly pursue it, and even the Kekkaishi tradition, is a secret shame that Hazama carried alone for centuries, awaiting the arrival of a Kekkaishi talented enough to help him lift an endless curse.