Kalki is the tenth and final avatar of the Hindu god Vishnu, who will appear at the end of the present Kali Yuga age to punish the wicked, reward the good, and inaugurate the Satya Yuga age of sacrifice and dharma. It is also believed that Kalki will also kill the demon Kali.
Kalki is described in the Puranas as the avatar who rejuvenates existence by ending the darkest and destructive period to remove adharma and ushering in the Satya Yuga, while riding a white horse with a fiery sword. The description and details of Kalki are different among various Puranas. Kalki is also found in Buddhist texts: For example the Kalachakra-Tantra of Tibetan Buddhism.
The prophecy of the Kalki avatar is also told in Sikh texts.