Legend says that, in order for the protagonist (shite) to have time to change costumes, the role of the Noh farce pro was created to relate the two sessions of the Noh story.
前後でシテが装束を変えるために、その場をつなぐ目的で狂言方の役者が能の物語にまつわる古伝承や来歴を語るものである。