Tsuru is a formless life form from Planet Nuruba.
Tsuru, the brother of Suru, has lived his entire life on Nuruba. While his father tells him that having no form makes them the perfect beings, Tsuru and his sister long to take a form and experience what is like.
Tsuru was designed and created by Leiji Matsumoto, creator of the popular Galaxy Express 999 and Captain Harlock franchises, during the late 1970s.
Refusing to heed their father's wishes, Tsuru and Suru attack the Galaxy Express during a routine stop. They are successfully able to attack Tetsuro and Maetel and steal their form, but Tetsuro eventually is able to overpower them and the two end up being rescued by their father. Despite the failed attempt, the two say that they will continue to seek a form.