Gyūki (牛鬼, Gyūki), more commonly known as the Eight-Tails (八尾, Hachibi), is a tailed beast sealed within Tenka Nihisaki of Kumogakure after ten other jinchūriki failed to control, or were overcome, by him. He is friends with his jinchūriki and an active voice of reason and support for her during their time together.