There was an asura named Ramba who after observing penance to Lord Agni, received a boon. He wished for a son who would have supernatural powers and could never be killed by a god, man or animal. Agni granted him a son but in order for the child to gain powers and invincibility, he told Ramba to tell his son to pray to Lord Brahma when he grew up. Soon Mahishasura was born to Ramba, and when he grew up he observed severe penance to Lord Brahma.

Lord Brahma granted him the boon of invincibility and Mahishasura could not be killed by a man, god or animal. After gaining his powers, Mahishasura became hungry for power and control and soon started attacking kingdoms and destroying everything in his way. He even attacked the Devas in heaven and overthrew Lord Indra. All the gods were troubled by the destruction caused by Mahishasura and all the gods including Lord Brahma, Lord Vishnu and Lord Shiva gathered at Vaikunta to address the situation.

When the Gods gathered, the whole of Vaikunta echoed by a female voice. The voice was none other than that of Mahadevi (The Great Goddess) who told them that the boon did not grant Mahishasura invincibility from a woman. Hence, she requested the three Shaktis (Saraswati, Lakshmi and Parvati) to use their divinity and create a greater power; a warrior goddess who would bring the downfall of Mahishasura.

The three Shaktis followed the orders and combined together to form a reincarnation of Mahadevi who also came to be known as Durga (which means invincible). Goddess Durga emerged and was a warrior who had a thousand hands. All the gods gifted the Goddess a weapon of their choice, whereas the Lord of the Mountain Himalaya gave Durga a lion to be used as a vehicle.

Upon knowing about the birth of Goddess Durga, Mahishasura was terrified. He sent a large army to defy Goddess Durga but it was all in vain. Goddess Durga was the supreme power on the battlefield and easily destroyed Mahishasuras army. The battle ended when Goddess Durga finally killed Mahishasura, thus bringing an end to his terrible and tyrannical reign. Goddess Durga also came to be known as Mahishasuramardini (the one who killed Mahishasura).

Hence Goddess Durga is considered to be the universal power and she symbolises the divine powers required to vanquish evil in this world.