Kalki, Vishnu, and Kali

Kali
Vishnu

Kalki, the rider, and the tenth incarnation of Vishnu is yet to appear on earth. It is believed that Kalki will ride a white horse and wield a flaming sword with which he will destroy all evil. The coming of this fierce horseman will mark the end of this present age of evil, the Kali Yuga, after which purity will reign once again in another Treta Yuga.

In Hindu traditions, Kalki (Sanskrit: कल्कि; also rendered by some as Kalkin and Kalaki) is the tenth and final Maha Avatara (great incarnation) of Vishnu the Preserver, who will come to end the Kali Yuga, (The Age of Darkness and Destruction). The name Kalki is often a metaphor for "Eternity" or "Time". The origins of the name probably lie in the word Kalka which refers to "dirt", "filth" or "foulness" and hence denotes the "Destroyer of Foulness", "Destroyer of Confusion", "Destroyer of Darkness", or "The Annihilator of Ignorance". Other similar and divergent interpretations based on varying etymological derivations from the ancient Sanskrit language, including one simply meaning "White Horse", have been made

Kalki is also a novel by Gore Vidal.