Kaidou, known as 'Kaido of the Beasts,' is one of the Four Emperors and serves as a major antagonist in the anime and manga series One Piece. As the captain of the Beasts Pirates, Kaidou is renowned for his immense strength, near invincibility, and his desire to start the greatest war the world has ever seen. His role in the series is as the main antagonist of the Wano Country arc, where he seeks to dominate and reshape the world through chaos and power.