Land of Ninjas

Tailed Beasts

The tailed beasts (尾獣, bijū) are nine giant demons that serve to drive the plot of the Naruto series. They are differentiated by the number of tails they have, with each possessing a number from one to nine. The tailed beasts are large, living forms of chakra, sometimes referred to as "Chakra Monsters" (チャクラのバケモノ, Chakura no Bakemono), giving them power that far outmatches most shinobi. However, this immense strength is tempered due to their bestial nature, which restricts them from being intelligent enough to use it effectively. When tailed beasts are sealed within humans, they are able to benefit from the knowledge of their hosts, giving them the ability to better utilize their powers. There has only been a few shinobis who have complete control over their Tailed Beasts.. It is a near impossible tasks due to the beasts' immense power and bloodlust. The only ones who are capable in doing so are Madara Uchiha, Senju Hashirama, Yagura the Fourth Mizukage, Killer Bee of the Hidden Cloud, and Selika Hikari the Sixth Hokage.

In the beginning of ninja history, centuries before the founding of the ninja villages, there existed one demon, the Ten-Tailed Beast, that plagued the world until the Sage of the Six Paths defeated and sealed the beast within himself, making him the first jinchūriki. However, knowing that his death would release the Ten-Tails back into the world, the Sage used his ability, the Creation of All Things (万物創造, Banbutsu Sōzō), to divide its chakra into the nine other tailed beasts, before using Chibaku Tensei to seal its body away in what would become the moon. By the time of the formation of the shinobi villages, Hashirama Senju, the First Hokage, used his Wood Release techniques to capture and give several tailed beasts to the other shinobi villages as peace treaties, in order to stabilize the balance of power between them. However, after Hashirama's death, the villages had trouble containing these giant demons themselves and they began to run wild, so the villages instead moved to seal the tailed beasts within humans. In order to ensure that the jinchūriki wouldn't turn traitor, it has been common practice to choose the jinchūriki from the village's Kage family, such as a sibling or a spouse. The strength of the jinchūriki would then be used to protect the village and be a living display of the Kage's power. Throughout history, very few people have ever gained full control over a tailed beast.  Akatsuki has been capturing the tailed beasts and their jinchūriki, and as of the Fourth Shinobi World War, possess seven of the nine tailed beasts. Comments from both the Eight-Tails and the Nine-Tails indicates that they know each other on a personal level, but without any respect. Moreover, the Nine-Tails' reaction to Naruto's new seal indicated that it also had knowledge of the Sage of the Six Paths, and by extension the Ten-Tails.