Hannya | Yokai.com- oni mask vs hannya mask n99 ,Appearance: Hannya refers to demons or oni; more specifically to female demons called kijo—even more specifically to those kijo which appear in noh theater. They were once human women who were consumed by jealousy and transformed into demonesses. The name hannya also refers to a specific type of demon mask used in noh theater.Hannya - WikipediaThe Hannya (般若) mask is a mask used in Noh theater, representing a jealous female demon. It possesses two sharp bull-like horns, metallic eyes, and a leering mouth. Origin of the name. The name hannya (般若) is a Sino-Japanese word for prajna or wisdom. One tradition states that this name was given to this mask because it was the name of ...