Hindu traditions permit numerous interpretations of what avatars are and to what purpose they act. Avatara means "descent" and indicates a descent of the divine awareness into manifestations of the mundane form. The Garuda Purana lists ten avatars, with Kalki being the tenth. The Bhagavata Purana initially lists twenty-two avatars, but mentions an additional three for a total of twenty-five avatars. He is presented as the twenty-second avatar in this list.
All Hindu traditions declare all people to be manifestations of the divine essence or Atman and avatars to be individuals who are far more acutely and extensively aware of this fact and its implications than most. They have entered the mortal realms voluntarily to teach important truths to humanity or dharma, and usually have extraordinary abilities to aid in these roles.
Popular images depict him riding a white horse with wings known as Devadatta (God-given.) In these images, Kalki is brandishing a sword in his right hand and is intent on eradicating the corrupt destitution and debauchery of Kali Yuga. Others represent him as an amalgam of a horses head and a man's body.
The prophecy and its origins
One of the earliest mentions of Kalki is in the Vishnu Purana, which is dated generally to be after the Gupta Empire around the 7th century A.D. In the Hindu Trimurti, Vishnu is the preserver and sustainer of life, balancing the processes of creation and destruction. Kalki is also mentioned in another of the 18 major Puranas, the Agni Purana. Agni is the god of fire in the Hindu pantheon, and symbolically represents the spiritual fire of life and the processes of transformation. It is one of the earliest works declaring Gautama Buddha to have been a manifestation of Vishnu, and seems to draw upon the Vishnu Purana in its mention of Kalki. A later work, the Kalki Purana, a minor Purana, is an extensive exposition of expectations and predictions of when, where, and why it is said he will come, and what he is expected to do. It has a militant perspective, and celebrates the defeat of traditions that are deemed heretical for not adhering closely enough to the traditions of the Vedas, such as Buddhism and Jainism. A few other minor Purana also mention him.
The Agni Purana explains that when the non-Aryans who pose as kings begin devouring men who appear righteous and feed on human beings, Kalki, as the son of Vishnuyasha, and Yajnavalkya as His priest and teacher, will destroy these non-Aryans with His weapons. He will establish moral law in the form of the fourfold varnas, or the suitable organization of society in four classes. After that people will return to the path of righteousness. (16.7-9) The Agni Purana also relates that Hari, after giving up the form of Kalki, will go to heaven. Then the Krita or Satya Yuga will return as before. (16.10)
The Vishnu Purana also explains that, "When the practices taught in the Vedas and institutes of law have nearly ceased, and the close of the Kali age shall be nigh, a portion of that divine being who exists of His own spiritual nature, and who is the beginning and end, and who comprehends all things, shall descend upon earth. He will be born in the family of Vishnuyasha, an eminent brahmana of Shambhala village, as Kalki, endowed with eight superhuman faculties. By His irresistible might he will destroy all the mlecchas and thieves, and all whose minds are devoted to iniquity. He will reestablish righteousness upon earth, and the minds of those who live at the end of the Kali age shall be awakened, and shall be as clear as crystal. The men who are thus changed by virtue of that peculiar time shall be as the seeds of human beings, and shall give birth to a race who will follow the laws of the Krita age or Satya Yuga, the age of purity. As it is said, 'When the sun and moon, and the lunar asterism Tishya, and the planet Jupiter, are in one mansion, the Krita age shall return.'" (Book Four, Chapter 24)
The Padma Purana relates that Lord Kalki will end the age of Kali and will kill all the wicked mlecchas and, thus, destroy the bad condition of the world. He will gather all of the distinguished brahmanas and will propound the highest truth. He will know all the ways of life that have perished and will remove the prolonged hunger of the genuine brahmanas and the pious. He will be the only ruler of the world that cannot be controlled, and will be the banner of victory and adorable to the world. (6.71.279-282)
The Srimad-Bhagavatam states, "At the end of Kali Yuga, when there exist no topics on the subject of God, even at the residences of so-called saints and respectable gentlemen of the three higher castes, and when the power of government is transferred to the hands of ministers elected from the lowborn shudra class or those less than them, and when nothing is known of the techniques of sacrifice, even by word, at that time the Lord will appear as the supreme chastiser. (2.7.38) It further describes Lord Kalki's activities as follows: "Lord Kalki, the Lord of the universe, will mount His swift white horse Devadatta and, sword in hand, travel over the earth exhibiting His eight mystic opulences and eight special qualities of Godhead. Displaying His unequaled effulgence and riding with great speed, He will kill by the millions those thieves who have dared dress as kings." (12.2.19-20)
The Kalki Purana combines all of the elements from the puranas above. He is one who has power to change the course of time stream in the favour of the good. He will be one to whom the power to change the destiny of the world will be given. It states the evil family of the demon Kali will spring from the back of Brahma. They will descend to earth and cause mankind to turn towards depravity. When man stops offering yagna to the gods, Vishnu himself will descend to earth to rid the world of evil. He will be reborn as Kalki to noted Brahmin family in the city of Shambhala. As a young man, He will be mentored in the arts of war by Parashurama, the sixth incarnation of Vishnu. He will then set out across the world battling evil kings and false prophets. He finally defeats Kali and brings about the Satya yuga. Having completed His mission, He will assume his four-armed form and return to heaven as Vishnu.
Followers of Tibetan Buddhism have preserved the Kalachakra Tantra in which "Kalkin" is a title of 25 rulers of the mystical realm of Shambhala. The aims and actions of some of these are prophesied in portions of the work. The 25th Kalkin as an emanation of Manjushri is said to bring about worldwide spiritual change.
Many modern writers have attempted to link figures in comparatively recent history to Kalki. Given the traditional account of the Kali Yuga lasting 432,000 years  and having started in 3102 BCE , which makes these claims problematic. Some scholars such as Sri Yukteswar Giri and David Frawley have claimed that there are intermediate cycles within the 432,000 year cycle.
- Shree Veera Brahmendra Maha Swami, writing about 1,000 years ago in "Divya Maha Kala Jnana" (literally: "Divine Knowledge of the Time") claims that he would arrive when the Moon, Sun, Venus and Jupiter have entered the same sign; such occurrences are not rare and the next is expected in the year 2012 or afterwards.
Stone plaque of Kalki from the 18th century.
THE KALKI PURANA
We can now start our comparative analysis with the figure of Kalki as presented in the Epic and Puranic literature. As far as we know, the tenth avatar of Vishnu has not inspired any Hindu messianic movement of the revolutionary type nor does he seem to have played any significant role in the Medieval devotional movements (bhakti) centered mostly on Krishna or Rama, the most popular incarnations. If references to Kalki are found in the Epics as well as in a few Puranas such as the Bhagavata and the Visnu Puranas (Stutley, 1985: 138) the two major texts are undoubtedly the Bhavisya and Kalki Puranas. For this study the latter is certainly the more relevant as it deals in detail with the descent of the tenth incarnation, his life on earth, the various battles fought by him, his marriage and his final return to the Vaishnava paradise (vaikunth) via the Himalayas. The Bhavisya Purana, instead, describes future events preceding the coming of Kalki of whom comparatively little is said.
I will therefore focus on the Kalki Purana, quoting only occasionally from other Puranic or Epic texts, and present its main themes which will then be compared to both the Agam vanis and to the prophetic hymns of the Ismaili tradition.
Contrary to the Bhavisya Purana, which traditionally figures in the list of the eighteen great Puranas, the Kalki Purana is considered a secondary Purana (upapurana). It is also referred to as anubhagavata, being sometimes regarded as a sequel to the Bhagavata Purana belonging to the Vaishnava sectarian tradition (Norman, 1908). Nothing can be said for certain about its date of composition. The text may not be very old, but since it describes the triumph of the Brahmanical religion over Buddhism and Jainism viewed as heresies one can say at least that it reflects a period between the seventh and the twelveth centuries when these religious traditions were on the decline.
The central character of the Kalki Purana is the tenth avatar of Vishnu mostly referred to as Kalki. The etymology of this name is by no means clear. According to Norman (Ibid.: 88), "the name Kalki is derived from Kalka and would mean "the destroyer of what is foul'. The Marathi variant kalanki points to the same meaning. Some (...) derive the word from Kali and a root kai to destroy, but this is not authenticated". In his postface to the French translation of the Kalki Purana (Bhatt and Remy, 1983: 192) Preau stresses the ambiguity of the name: "The very name of Kalki or Kalki (both forms are found) is intriguing because kalka in Sanskrit means 'dirt', 'stain'. Actually the name of Kalki is perceived by Abegg as an antithesis, whereas, according to the Kalki Purana, Kalki would mean 'he who removes sin or blemish from the world', Kalki being sometimes referred to as kalkavinasana, 'the destroyer of blemish' ".
In other texts Kalki is known by alternative names such as Parasraya in the Visnu Purana (Stutley, 1985: 138) and Visnuvyasa in the Mahabharata, the Vayu Purna and the Harivamsa (Bhatt and Remy: 192). Curiously enough he is nowhere, as far as I know, referred to as Niskalank although this Sanskrit adjective meaning "immaculate" or "stainless" - otherwise used to designate the Absolute or formless God - would certainly suit him better than the obscure form Kalki.
His story as told in the Kalki Purana can be summed up as follows. The future avatar of Vishnu, said to be the son of a Brahmin named Visnuvyasa, has received from the god Shiva a miraculous sword, a parrot and a winged horse of white colour whose name - given as Devadatta (litt. "given by the gods") in the Bhagavata Purana (Stutley, Ibid.) - is not indicated in this text. His fiercest enemy for whose destruction he will become incarnated is Kali or Kali Yuga, the personification of the last of the four yugas, symbolizing all its evils. But Kalki will also have to fight against human enemies, mainly represented by Buddhists and Jains. After his victory he will marry two Ksatriya princesses and his mission on earth being accomplished he will retire to the Himalayas where he will spend his days in meditation.
Norman (Ibid.: 88) views the Kalki Purana as "a strange jumble of featureless character, convention battles, allegorical ideas, and hymns in praise of Visnu, Siva and the Ganga. The hero has nothing but his divinity to distinguish him from the typical princes of a Kavya. His performance is nothing more than the Digvijaya of a Cakravartiraja". Indeed one of the most striking traits which should be mentioned is the highly allegorical nature of most characters including the evil spirit of Kali Yuga (other yugas also appear in an anthropomorphic, personified form): for instance he is said to be the son of Krodha (anger) and Himsa (violence) (Bhatt and Remy: 192). The description of the evils of Kali Yuga is more vivid although it is mainly reduced to a list of transgressions against the Brahmanical socio-cosmic order (dharma): confusions of castes, mixed marriages, wrong behaviour of women, ignorance of Brahmans, pride of the low castes or sudras, etc. The Age of Kali Yuga is clearly represented as the rule of adharma but one does not find any extensive description of cataclysms or disasters. The only allusion to the disorder of nature is perhaps the comment, "the storm clouds will strangely rumble" (Bhatt and Remy: 26). The final victory over Jains and Buddhist is obviously meant to demonstrate the superiority of the Brahmanical dharma and of the high varnas: Kalki is portrayed as the son of a Brahman who, becoming a king, weds two Ksatriya princesses.
The general atmosphere of the passages of the Ramayana (both Valmiki's and Tulsi Das' versions) dealing with this theme is similar insofar as they emphasize the triumph of the Vedic and Brahmanical order, as does the interesting fragment of the Bhagavata Purana (Chapter 8) describing the end of Kali Yuga. This text contains, however, a few accents which differ from the Kalki Purana and are therefore worth mentioning here. The advent of Kalki, the restorer of dharma and destroyer of mlecchas (a term referring to "barbarians" and heretics outside the pale of the Brahmanical order) which is rather briefly alluded to is preceded by a vivid description of the evils of Kali Yuga. Besides the usual transgression of dharma (disruption of the caste system, misbehaviour of men and women, etc.) a few abnormalities are described: there will be no more rainfall on the earth, the life of human beings will be very short and they will grow old at the age of twenty, while very young girls will give birth to children.