Devi Mahatmyam describes the story of how Devi (mother Goddess) killed Madhu and Kaidabha as Vishnu Maya (Thamasic-base), killed Mahishasura as Lakshmi (Rajashic form-materialistic) and killed Shumbha and Nishumbha in the form of Goddess Saraswati (Sathvic-spiritual). It is mentioned in the Markandeya purana. Devi Mahatmyam is also known as Saptashti because it contains 700 mantras (7= sapta and 100=ashta.) and 518 verses. There is another opinion that the name should be Saptasati as it deals with the story of seven Satis .The seven mothers are Brāhmi, Māheśwari, Kaumāri, Vaisṇavi, Vārāhi, Indrāṇi, and Chāmunḍa.
One of the important parts of this Holy Scripture is the stories of Markandeya which explain stories that lord Markandeya narrated to Jamini and his students. These stories talk about the brave conquests of the Devi against several demonic forces. The most one that all of us are invariably familiar with is the mahishasura mardini story.
The story of how Durga came into being is quite familiar to all of us. Mahishasura was the most dangerous and evil demons on the face of earth. So the gods decided to give all their powers and weapons to vanquish their enemy. In course of the battle, the demon took several forms including that of a buffalo but Durga Devi slayed his head and brought him under her feet.
Kali is generally associated with great evil and destruction. Kali the dark goddess during her battle with the demon Raktabhija was quite surprised because from every drop of his blood that spilled, another demon arose but goddess Kali would not give up. She drank all the blood of Rakabhija and in frenzy began dancing and it wasn’t until Shiva intervened that she stopped.
Similar to lord Rudra, there are two forms to the goddess too. One is the nurturing and compassionate mother of the universe and the other the fiery warrior. Both lalitha sahasranamam and Devi mahatmyam are an ode to goddess’s victory over demons. Devi Mahatmyam describes the victory of the Goddess over the asuras Madhu-Kaitabha, Mahishasura and Shumbha-Nishumbha.
Most of Devi Mahatmyam describes battle scenes and praises of the Devi but even these lines are considered as mantras.
Various forms like Durga, Chandi, Mahakali, Mahalakshmi and Maha Saraswati are but Her divine forms. Each form of the Devi has a distinctive role meant for a definite purpose. Yet every form is also identified as the Ultimate Reality of the universe. Each form of the Divine Mother is thus an embodiment of the Supreme Divinity. One form may appear different from the other. But they are all a manifestation of the Supreme Shakti, whom some might call as Brahmam or Adi Parashakti.