Kalki is the form that Vishnu will assume at the end of this cosmic age, the Kali Yuga. As Kalki, Vishnu will appear in a human form riding on a white horse. He will bring a fiery end to the world, reward the virtuous, and punish the wicked. With his advent, evil will disappear, and the Krita Yuga (also known as the Satya Yuga, the age of truth) will begin again.