weak tengu; lesser tengu
Refers to a low-ranking or weak tengu in Japanese folklore, often contrasted with more powerful tengu. The term is a fixed expression.
See also: 天狗
Konoha-tengu are said to be weaker than great tengu.
天狗 is the general term for tengu; 木の葉天狗 specifically denotes a weak or lesser variety.
Compound of 木の葉 (このは, 'leaf of a tree') and 天狗 (てんぐ, 'tengu'). The exact origin is uncertain, but the name likely evokes the image of a small, leaf-like or weak tengu.