Kalratri Deviis the most ferocious form ofGoddess Durga, incarnated to kill Shumbh and Nishumbh demon brothers, is worshipped on 7th day. Her name literally means the dark night of the time or the destroyer of time. She is the controller of every night of time. She is also known asKali because of her black complexion, and Chamunda for killing Chand and Mund demons.
Worshipping goddess Kaalratri can remove all the fears, make the devotees bold and self-confident. She is the remover of all evil, negative intentions, spells and black magic. It also provides protection and mystic powers.
According to puranas, demons kept wrong intentions of owning other woman against her wish. For destroying them goddess transformed into fierce forms of Durga, Kalratri, chandi, chamunda or kali. Also stated in puranas, Lord Shiva jokes on Goddess Parvati and converts her complexion to dark which resulted in her being annoyed and change into kalratri form. Kalratri did very severe penance of Brahma to get transformed into Mahagauri. It is a very common practice of joking on women on her various flaws or keeping wrong intentions for other woman. People should learn from this n fear that such karma creates a fierce energy of Kalratri/ Kali which destroys the wrong.
One can pray to her by following mantras-
Om Devi Kalratryainamah
Vardhanamurdhadhwaja Krishna kalratrirbhayankari.