Tengu are a Japanese supernatural creature. In art, they are usually depicted with both bird and human characteristics. They are often shown wearing a small cap and a pom-pom sash and sometimes carry a feathered fan. Tengu are sometimes depicted as having red faces with long noses.
Touhou has some tengu characters, Shameimaru Aya and Himekaidou Hatate. These normally look like girls, and should not be tagged with tengu unless they're looking particularly demon-like.