Kalki Purana details about events believed by Hindus that would occur in the future. The work consists of passages that are collected from various Puranas describing the same subject. It describes the onset and exponential increase of evil on the earth during the Kali Yuga. It also explicates life of Kalki avatar who is said to bring an end to the darkness of the Kali Yuga.
According to Kalki Purana, demon Kali will rule the earth and bring sin and misery to the people. In the first stage of Kali Yuga varna system deteriorates. The second, third, and fourth stages of the Kali Yuga begin. During the second and third portions men would forget the name of God and no longer offer Yajna to them. In the fourth stage During the Canibalism would be universal among the humans. When the Yuga ends, the Devas will then journey to Vaikunta in order to seek help from Lord Vishnu. Thereafter he would descend on Earth to fix these problems of the Kali Yuga.
Lord Vishnu comes to earth in Sumati's home, the wife of the Brahmin Vishnuyasha. Kalki will be born in the lunar month of Vaishakha, on the twelfth lunar tithi and he would spend his childhood in the mystical kingdom of Shambhala. Kalki will begin martial training under Parasurama after Chiranjeevin immortals gather in Shambhala.
He would begin a penance to Lord Shiva after his martial training under Guru Parashurama. He would receive the winged steed Devadatta, the celestial parrot Shuka and the divine "Ratna Maru" sword from Lord Shiva. He would marry Padma, the avatar of Vishnu's heavenly consort Lakshmi and have two sons Jaya and Vijaya. Kalki would also perform the Ashvamedha sacrifice in order to liberate the world of all wicked kings and false prophets.
Lord Vishnu would come to earth as Kalki in order to destroy and defeat evil forces. He would begin this by killing the Sunyavadis, who have misled the people. A war is also waged with the dark forces of Kali that also includes the demon generals Koka and Vikoka fighting against Kalki and the Devas. Kali will be defeated by Dharma. Ultimately Kalki would accept defeat from Raja Shashidhwaja and marry the Raja's daughter, his second wife Ramaa.