Durga is the mother Goddess – the Supreme Power. She has numerous manifestations. While some of these forms are benign, others are fierce and instill fear in the minds of the demons and the wicked.
In her benevolent forms she is Uma (light), Gauri (brilliance), Sati (chastity), Parvati (daughter of mountains) and Jagatmata (the mother of the universe).
In her fierce manifestations, she is Durga (the insurmountable), Kali (the black), Bhairavi (the terrible) and Chandi (the fierce). Keep in mind that these are just some of her manifestations. Put simply, Durga is the creator and the destroyer.
Durga – Origin
Durga first appeared as a beautiful warrior woman seated upon a fierce tiger. She assumed this form to put an end to the tyranny of the demon king Mahishasur. The demon had performed austerities for a long time and won invincible strength. Even Vishnu or Shiva could not defeat him. This necessitated the birth of Goddess Durga. She possesses the combined power of all the gods and goddesses. Legend has it that armed with the best weapons and the combined power of Shakti, eighteen armed Durga set out to defeat Mahishasur on the new moon day of the month of Ashwin.
Durga mounted a ferocious lion and went to the battlefield. She is the angry and aggressive manifestation of Sakthi (the female energy that sustains the universe) and the very purpose of her existence is to destroy the wicked. Durga also personifies the female aspect of male deities. The battle lasted for nine days and nights and on the tenth day, Durga killed the demon. This day is now observed as Vijayadashami (the day of victory). Hindus invoke Durga for protection from evil forces. Nine forms of Durga are worshipped during Navaratri. In Bengal the last five days of Navaratri are meant for the worship of Durga.
Hindus have been worshipping Durga for thousands of years. Her name is mentioned in Vedic literature and Hindu epics like Ramayana and Mahabharata. Every Hindu worships Durga. While some love her gentler manifestations, others are in awe of her fierce forms. Generally speaking, Durga worshipped in North India possesses gentle bride like qualities whereas in South India, her warrior aspects are worshipped. In Bengal and north east India also Durga is worshipped in her fierce form as Kali.