Katyayini is the sixth form amongst the Navadurga or the nine forms of Hindu goddess Parvati or (Shakti), worshipped during the Navratri celebrations. This is the second name given for Parvati in amarakosha, the Sanskrit lexicon. (Uma Katyayani Gouri Kali Haimavathi Iswari) In Shaktism she is associated with the fierce forms of Shakti or Durga,a Warrior goddess, which also includes Bhadrakali and Chandika, and traditionally she is associated with the colour red, as with Goddess Durga, the primordial form of Shakti, a fact also mentioned in Patanjali’s Mahabhashya on Pāṇini, written in 2nd BCE.
She is first mentioned in the Taittiriya Aranyaka part of the Krishna Yajurveda. Skanda Purana mentions her being created out of the spontaneous anger of Gods, which eventually led to slaying the demon, Mahishasura, mounted of the lion given to her by Goddess Gauri. This occasion is celebrated during the annual Durga Puja festival in most parts of India.
Her exploits are described in the Devi-Bhagavata Purana and Devi Mahatmyam, part of the Markandeya Purana attributed to sage Markandeya Rishi, who wrote it in Sanskrit ca. 400-500 CE.
In Hindu traditions like Yoga and the Tantra, she is ascribed to the sixth Ajna Chakra or the ‘Third eye chakra’, and her blessings are invoked by concentrating on this point.
According to ancient legends, she was born a daughter of Katyayan Rishi, born in the Katya lineage, thus called Katyayani, “daughter of Katyayan” . Elsewhere in texts like the Kalika Purana, it is mentioned that it was Rishi Kaytyayan who first worshipped her, hence she came to known as ‘Katyayani. In either case, she is a demonstration or apparition of the Durga, and is worshipped on the sixth day of Navratri festival.
The Vamana Purana mentions the legend of her creation in great detail: “When the gods had sought Vishnu in their distress, he, and at his command Shiva, Brahma, and the other gods, emitted such flames from their eyes and countenances that a mountain of effulgence was formed, from which became manifest Katyayini, refulgent as a thousand suns, having three eyes, black hair, and eighteen arms. Siva gave her his trident, Vishnu a Sudarshan Chakra or discus, Varuna a shankha, a conch-shell, Agni a dart, Vayu a bow, Surya a quiver full of arrows, Indra a thunderbolt, Kuvera a mace, Brahma a rosary and water-pot, Kala a shield and sword, Visvakarma a battle-axe and other weapons. Thus armed, and adored by the gods, Katyayini proceeded to the Vindhya hills. There, the asuras Chanda and Munda saw her, and captivated by her beauty they so described her to Mahishasura, their king, that he was anxious to obtain her. On asking for her hand, she told him she must be won in fight. He came, and fought; at length Durga dismounted from her lion, and sprang upon the back of Mahisha, who was in the form of a buffalo, and with her tender feet so smote him on the head that he fell to the ground senseless, when she cut off his head with her sword, and hence was called Mahishasuramardini, the Slayer of Mahishasura., the legend also finds mention in Varaha Purana, and the classical text of Shaktism the Devi-Bhagavata Purana