|Eight-Tails (八尾, Hachibi)|
|Appears in||Anime, Manga, Game|
"Possibly humans can exist without actually having to fight. But, many of your kind have chosen to fight. For what reason? To protect something? Protect what? Yourselves? Your future? If you kill people to protect yourselves and this future then what sort of future is it and what will you have become? There is no future for those who have died. And what of those who did the killing? Is happiness to be found in a future that is grasped with blood stained hands? Is that the truth?."
The Eight-Tailed Giant Ox (八尾の巨牛, Hachibi no Kyogyū) is a tailed beast sealed within Kisuke Kagami, a ninja of Kumogakure. It was previously sealed within Kai Saizu, an unknown fourth jinchūriki, and Killer Bee, all of them from Kumogakure.
According to Madara Uchiha, the Eight-Tails came into being near the end of the waning days of the Sage of the Six Paths' life; to prevent its resurgence, the Sage split up the demon's chakra of the Ten-Tailed Beast into nine separate, monstrous constructs of living chakra, which would become known as the tailed beasts. The Eight-Tails eventually fell into the possession of Kumogakure and was sealed into Killer Bee, and later Kurisu. After Akatsuki fell, the Eight-Tails roamed wild until it was captured and sealed by Riyan Uchiha.
The Eight-Tails resembles an ushi-oni with three long horns and a short left horn. It has an upper-body structure of a human, but has no hind-legs. Its 'tails' are really eight cephalopod arms of an octopus, and according to it's former host, Killer Bee, its tails are able to eventually grow back even after they were being cut off.
Kisuke and the Eight-Tails appear to be able to speak to each other in a much more relaxed state than most jinchūriki and their Tailed beasts can. For example, when Naruto had a conversation with the Nine-Tails, the latter is in a cage with a special seal keeping it from taking over Naruto. As Kisuke is one of the few people who has total control over his own tailed beast, he and the Eight-Tails can talk without such restraints, with Kisuke even sitting on top of its muzzle.
However, despite Eight-Tails' friendly relationship with Kisuke, the Eight-Tails, like the other beasts, main goal is self preservation. For example, it was more than willing to be released and destroy it's old host, Kai Saizu, despite Seireitou and Hikaru being close by. However, behind the brutal appearance the Eight-Tails is shown to have a good analytical ability, as he told his former host, Killer Bee, that if he left Ponta and Sabu and run in the opposite direction Kisame and the water will follow him and they (Sabu and Ponta) will be free.