The Mushinoiki family (虫の息一門, at death's door) is one of the oldest clan's of Iwagakure and was one of the first clan's to live their during the village's founding. They are the only known users of the "curse" known as the Korōshibyō. With this Kekkei Genkai, they can enter a more beastly mode in which they become skill fighters with the instincts of an animal.