Demon mask is a type of mask that made up of demon bones,[1] it is used for controlling victim as he wears on.
During the Heian jidai, a powerful monk defeated the mask, until in 1000 AD, a cat hanyō Gorai, Lord of the Northern Lands, who came from the Northern Lands, stole the masks from the horoka shrine near Izayoi's mansion. The next day, he later interrupted the wedding ceremony between Datara and Tsugumi by forcing Datara to wear the demon mask while holding his daughter hostage. This turned him into an instrument of destruction for yōkai. As soon as Datara wore it, however, Tsugumi used the Arrow of Sealing to seal her husband to prevent him from unleashing his power for evil.
500 years later, Gorai sent Monk Sen to lure Inuyasha and the others to undone the seal of Datara at Datara's shrine. Although Janis successfully removed the arrow from Datara's chest, Gorai still did not have any idea to obtain Datara's kamuitama, since it was too hard to control by a hanyō like him. After Inuyasha and the others defeated Gorai and Datara at Tempest Tower, Janis returned her kamuitama to Datara, the demon mask slowly slipped down from his face and broke into pieces. Datara was no longer being controlled.
