The nine-tailed demon fox is the most powerful of the tailed beasts. It is regarded as an age-old natural disaster, as a single swipe of one of its tails can raise tsunamis and flatten mountains. Twelve years before the start of the series, the fox attacked Konohagakure. Its attack was stopped by the Fourth Hokage, who gave his life to seal the fox into his son, Naruto Uzumaki. [wikipedia]
