Kokuo, also known as the Five-Tails, is a tailed beast in the Naruto series. It resembles a white horse with a dolphin's head, and it possesses immense strength and chakra. Initially captured and sealed within Han of Iwagakure, Kokuo is eventually released during the Fourth Great Ninja War. Despite being a beast, Kokuo exhibits a calm and composed demeanor, demonstrating an ability to communicate respectfully with other tailed beasts and humans. Throughout the series, Kokuo plays a vital role in the balance of power among the tailed beasts, contributing to the overarching narrative of peace and understanding.