Hantengu takes on the appearance of a short, frail man with a very thin and skeletal body covered in veins and wrinkles and is usually seen crouching. Its most notable feature is a large bump on top of its head, accompanied by two curved horns.

His face is thin, with a pointed chin, and he constantly wears an expression of terror and fear, with a prominent eyebrow that has no eyebrows. His eyes are narrow and often appear to be squinted, with no visible pupils.

He has dark, wavy, shoulder-length hair with a low hairline, only growing at the back of his head, and ears, which are sharper and longer than normal humans.