The Glory of the Goddess as narrated in chapter 5-13 (Third Charitra)
Shumba and Nishumba (represnting 'I' and 'mine') hear about the Luminous Devi, taken abode in the Himalaya. The evil asuras (deluded by kama) covet the Devi and ask her to marry either of them. The Devi states that the one who can conquer her in battle and equal her might alone will be Her husband.
The enraged Shumba -Nishumba send Dumralochana to bring the Goddess by force. By the mere heave of Her breath Ambika reduces the demon to ashes. Thereafter the asura army headed by Chanda and Munda battle the Devi. Seeing them, Kali, of terrible countenance, emerges from the Devi's forehead and severed the head of Chanda and Munda -thus getting the name Chamunda.
Sumbha now clouded by rage, commanded various Asura clans and raged at Chandika. In return the effulgent shakthi from each of the Gods along with their weapons and mounts emerge- Brahmani with a rosary from Brahma, Maheswari with the trident, and serpent ornaments mounted on the bull from Eshwara, Kaumari as the mother of skanda wielding the spear and riding on a peacock, Varahi from Lord Hari's form as the boar, Vaishnaviwith the conch and club on the Garuda, Aindri holding the thunderbolt mounted on the elephant.
The supreme Goddess then sends Lord Shiva as her ambassador in an attempt to make peace, by which She came to be called Shiva-Duti
The indignant Asuras were however on a path of self-destruction (it is our false sense of ego that leads to our downfall) and rushed towards the Goddess and her forces (Maatru Ganas). As the asura army was being destroyed the terrible Asura Raktabija rose in wrath.
As soon as a drop of blood from Raktabija fell on the ground another asura of equal might spring forth. To combat the hundreds of Raktabija (the thousands of thoughts that constantly arise which in turn lead to desire, resulting in frustration) arising out of his bleeding wounds inflicted by the Devi, Chamunda keeps her mouth open drinking in all the blood before they fell on the ground. Battered by the various weapons and drained of his blood Raktabija is killed.
The various manifestations of the Devi merge into Herself and then follows a fierce battle between the Devi and Shumba-Nishumba (the ahamkara) who are eventually slayed by the mighty Goddess.
The climax of the battle is thus between our limited sense of self(ego) and the Supreme Self. It is a spiritual battle beyond the realm of day to day life. It is here that the Devi Herself assures that concentrated and devout recitation of this Mahatmayam is certain to enable us realise the Supreme Self within oneself.