In the Markandeya Purana, compiled by Rishi Markandeya, there is a section illustrating victory of Mata Durga over strong and powerful demon Mahishasura, which is known as Devimahamatyama. But Devimahatmyam also talks about various other avatars of Mata Parvati.
According to Devi Mahatmyam, the entire universe was under the terror of demon brothers Shumbha-Nishumbha, who won the competition held by Shukracharya, the asura-guru to choose a new demon king. The runners up, i.e., Rakthabeeja, Dhumralochana and the demon brothers, Chanda-Munda, were made the commanders of the demon army setup by Shumbha-Nishumbha. The demon duo was able to spread its terror across the three worlds, heaven, hell and the netherworld.
They snatched everything from the Gods and even took control of Airavat, the royal elephant, the vehicle of Devaraja Indra. When everything seemed so bleak and negative, the Gods along with the Trideva, i.e., Brahma, Vishnu and Mahesh decided to visit the Vindhyachal mountain ranges to seek blessings and path of enlightenment from Mata Bhagwati. The gods were singing hymns and prayers but without taking any name of any goddess. Opposite to where the Gods were assembled, Mata Parvati was finishing her bath. She came towards the direction of the Gods and asked about the goddess for which they were singing the hymns and stutis. But the image of Bhagwati was unknown even to the Trideva. Thus all of them remained silent. Mata Parvati enquired again, still all of them were silent. All of a sudden, a goddess emerged from within Mata Parvati and introduced herself as Bhagwati. She told Parvati that the Gods were singing hymns in her praise. She cannot be defined into forms and figures. She can be felt within every individual and within every creature of this universe. Since the goddess emerged from within the body of Mata Parvati, she is also called by the name Kaushiki.
Standing afar from the place, a few demon soldiers were witnessing the entire episode. They looked at Mata Kaushiki and were mesmerized by her beauty. They returned to Shumbha-Nishumbha and told them everything about what happened. They further said that since the demon duo is supreme to all, is superior in everything they do and have possessed the best of the best things in the universe, thus they must also take possession of the most beautiful woman in the universe and should make her their wife and enjoy her service. The brothers were very convinced with whatever was told by the demon soldiers and ordered their demon messengers to ask devi Kaushiki to accept their proposal of marriage. Upon reaching Vindhyachal ranges, the messengers told Mata Kaushiki about the marriage proposal sent by demon king duo Shumbha-Nishumbha. Mata Kaushiki rejected the proposal and replied that she has taken a vow to marry only that man who will defeat her in a battle. The messengers returned and narrated everything to their kings. The demon brothers were very furious upon listening to this and considered a battle with a woman as their insult. They, consequently, sent their commanders, Chanda-Munda to drag Devi Kaushiki to their abode by pulling her hair and treating her devastatingly.
When Chanda-Munda reached Vindhyachal, they saw Mata Kaushiki and began laughing, trying to mock the Devi as someone who is weak and feeble and on whom they will pity to conduct their tortures. Mata became very furious and raised her eyebrows, from where a new and a much ferocious avatar of Mata emerged. She looked somewhat similar to Mata Kali in her personality and conduct. Mata Kaushiki ordered the new Devi to kill Chanda-Munda. The demon brothers had good control over thunder, lightning and static electricity. In a fierce battle between Mata and Chanda-Munda, that lasted for several hours, Mata killed the demon brothers and sent them back to their kings, Shumbha-Nishumbha. Mata Kaushiki told the devi that since she has killed powerful demon brothers Chanda-Munda, she will be known as Mata Chamunda.
Mata Chamunda is considered as one of the most ferocious avatars of Mata Parvati. She is the goddess of strength, valour and bravery. She resides either in figs trees or in cremation sites. She is accompanied by Lord Shiva in his Bheehshan Bhairav. Her mount is a haunting ghost and she holds the possession of swords and trident as her weapons. Mata Chamunda is widely worshiped across India.