Once, the demon Mahishaasur performed severe penance to propitiate Brahma. Pleased with his austerities, Brahma granted him the boon he requested that, if he should die, then it should be at the hands of a woman.
Jubilantly, Mahishaasur hurried back on his mission to defeat the Devas. So powerful was he that he managed to dethrone Indra, King of the Gods. He also dispossessed the Gods of their positions. Driving the Devas out of Swarga (heaven), Mahishaasur ascended Indra’s throne and assumed kingship himself. Thrown out of their realm, the Gods wandered aimlessly in the mundane world. At last, sorely distressed, they approached Lord Brahma, Bhagavan Shiva and Lord Vishnu and related their pathetic tale.
Even as the Devas spoke, an intense light issued forth from the faces of Brahma, Vishnu and Shiva. This was followed by similar rays of light from Indra and the other Devas. Out of that light emerged a female form with a thousand arms. It was Devi.
The Devas spoke to her, “O Devi! You are the origin of all worlds. You are the inner force, the source of all strength. Destroy Mahishaasur and protect us!” Then Lord Shiva drew forth a trident and offered it to her. Lord Vishnu and other Devas also offered weapons to her. Armed with the celestial weapons and mounting a lion, Devi emitted a loud roar and headed towards Mahishaasur.
A deadly confrontation took place between them. Devi leapt upon him, pinned him down and struck him with a sword. The enemy was finally defeated and the Devas were delighted. They all regained their positions and praised the Divine Mother.