Han'nin is a generic Japanese term meaning "the culprit" or "the criminal," and in Meitantei Conan it is often used as a placeholder label for the unknown perpetrator of a case. Rather than being a single recurring named character, Han'nin refers to the person responsible for the crime in a given episode or chapter. This role is central to the series’ mystery structure, since Conan and the other detectives work to identify and expose the culprit through deduction and evidence.