Kokuō

Kokuō primarily resembles a white horse, but with a dolphin's head. It has two pointed long horns and three (two in the anime) shorter horns in front. The ends of its horns, hooves, and tails are tan, with some of the same-coloured spots before the tan areas of its horns and hooves. It also has red markings under its dark blue-green eyes. During the last remaining days of the Sage of Six Paths, Kokuō was much smaller than it is now and its horns were also shorter.

Kokuō and the tailed beasts first came into being in the waning days of Hagoromo Ōtsutsuki, who used his Creation of All Things Technique to divide the Ten-Tails' chakra into nine separate bodies and giving each a name. Some time after being created, the Sage explained to the young tailed beasts that a link existed between them despite their separation. He also foretold of a day when they would be brought together again - though not as they were - and that at that time someone would emerge to show them what true power is. In the anime, before his death, Hagoromo sent Kokuō to live in a temple built for the purpose of protecting it in a forest region. During the First Shinobi World War, Hashirama Senju captured eight of the tailed beasts and sold Kokuō and Son Gokū to Iwagakure at the Five Kage Summit, as a sign of friendship and to ensure a balance of power amongst their new villages. The tailed beast would end up being sealed within Han, but was captured and extracted by Akatsuki.