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. Kokuō seems to be a quiet and reserved individual. Though it does not speak much, Kokuō comes across as very polite. It can use Fire Release and Water Release, as well as a unique ability named Boil Release.