There is no specific character or entity known as the "katana devil" in mythology, folklore, or popular culture. The term "katana devil" does not refer to a recognized or established figure in relation to katanas or any associated legends.

It's possible that the term "katana devil" may be a creative concept or a reference to a fictional character from a particular work of fiction, such as a novel, comic book, or video game. If you have any specific context or additional information about the "katana devil," I could try to provide more accurate information based on that context.