Tengu (Japanese: 天狗, "heavenly dog") are a type of legendary creature found in Japanese folk religion and are also considered a type of Shinto god (kami) or yōkai (supernatural beings). Although they take their name from a dog-like Chinese demon (Tiangou), the 'tengu were originally thought to take the forms of birds of prey, and they are traditionally depicted with both human and avian characteristics. The earliest tengu were pictured with beaks, but this feature has often been humanized as an unnaturally long nose, which today is widely considered the tengus defining characteristic in the popular imagination.
Buddhism long held that the tengu were disruptive demons and harbingers of war. Their image gradually softened, however, into one of protective, if still dangerous, spirits of the mountains and forests.
During the 14th century, the tengu began to trouble the world outside of the Buddhist clergy, and like their ominous ancestors the tiāngǒu, the tengu became creatures associated with war. Legends eventually ascribed to them great knowledge in the art of skilled combat.