This vowed religious observance was advocated by Sage Narad to Lord Rama, so that Lord Rama could slay the evil Ravan. After completion of this observance, Rama attacked Ravan's kingdom, Lanka, and slayed Ravan.

    The female deity (Devi) combated the demon Mahishasur for nine days from the first (pratipada) to the ninth day (navami) and finally slayed him on the ninth night. Since then She has come to be known as 'Mahishasuramardini', the slayer (mardini) of Mahishasur. The word 'asur' (demon) means the one who remains engrossed only in worldly (temporary) and object pleasures.