Mahishasur – the son of Rambhasur had captured the heaven after defeating the deities. The sorrowful deities came to seek the help of lord Vishnu and Lord Shiva.
Lord Shiva and Lord Vishnu became extremely furious after hearing about the misdeeds of Mahishasur. Radiant lights appeared from the bodies of Vishnu, Shiva and other deities and collectively manifested into a single form of Mahalakshmi. All the deities presented their respective weapons to her.
Mahalakshmi went to fight Mahishasur, who fought valiantly by changing his appearance, but ultimately got killed by her. The deities became very pleased by the death of Mahishasur. They eulogized and worshipped her.