Dhumavati (Sanskrit: धूमावती, Dhūmāvatī, literally "the smoky one") is one of the Mahavidyas, a group of ten Tantric goddesses. Dhumavati represents the fearsome aspect of Devi, the Hindu Divine Mother. She is often portrayed as an old, ugly widow, and is associated with things considered inauspicious and unattractive in Hinduism, such as the crow and the Chaturmas period. The goddess is often depicted on a horseless chariot or riding a crow, usually in a cremation ground.
Dhumavati is said to manifest herself at the time of cosmic dissolution (pralaya) and is "the Void" that exists before creation and after dissolution. While Dhumavati is generally associated with only inauspicious qualities, her thousand-name hymn relates her positive aspects as well as her negative ones. She is often called tender-hearted and a bestower of boons. Dhumavati is described as a great teacher, one who reveals ultimate knowledge of the universe, which is beyond the illusory divisions, like auspicious and inauspicious. Her ugly form teaches the devotee to look beyond the superficial, to look inwards and seek the inner truths of life.
Dhumavati is described as a giver of siddhis (supernatural powers), a rescuer from all troubles, and a granter of all desires and rewards, including ultimate knowledge and moksha (salvation). Her worship is also prescribed for those who wish to defeat their foes. Dhumavati's worship is considered ideal for unpaired members of society, such as bachelors, widows, and world renouncers as well as Tantrikas. In her Varanasi temple, however, she transcends her inauspiciousness and acquires the status of a local protective deity. There, even married couples worship her. Although she has very few dedicated temples, her worship by Tantric ritual continues in private in secluded places like cremation grounds and forests.
Source : WikiPedia