A Kagune is a biological weapon used by ghouls in the anime and manga series Tokyo Ghoul. It is an organ that manifests from the body, allowing ghouls to fight and defend themselves. Each kagune has a unique shape and ability, depending on the individual ghoul's characteristics. Kagune are classified into four main types: Rinkaku, Koukaku, Bikaku, and Ukaku. Each type has distinct traits, such as strength, speed, and durability. Ghouls can use their kagune for offensive and defensive purposes, making it a crucial aspect of their survival in a world where they are hunted by humans.