Oi no bakemono
Translation: backpack monster
Habitat: homes and temples where pilgrims might stay
Appearance: Oi no bakemono are tsukumogami—artifact spirits—which haunt wooden backpacks known as oi. An oi which has been used for a very long time may transform into this bird-like yōkai. They sproud heads with long, black hair, and three-toed avian feet Their carry a broken sword blade in their mouths, resembling a bird’s pointed beak. They can breathe fire.
Origin: Oi are special backpacks which are carried on long journeys by itinerant Buddhist monks, pilgrims, and yamabushi (mountain ascetics who practice Shugendō). They contain Buddhist religious implements, clothing, tableware, and other necessities for their journeys.
Oi no bakemono appears in the book Ehon musha bikō, where one is said to have appeared in the bedroom of Ashikaga Tadayoshi—a general and government administrator during the 14th century. Tadayoshi helped his brother Tadauji to establish the Ashikaga shogunate, which ruled Japan for over 200 years.