Durga (Sanskrit: दुर्गा Durgā ‘invincible’, Hindustani pronunciation: [ˈd̪ʊrɡaː]) is the principal form of the Mother Goddess in Hinduism. There are many incarnations of Goddess Durga: Kali, Bhagvati, Bhavani, Ambika, Lalita, Gauri, Kandalini, Java, Rajeswari, and has nine appellations: Skandamata, Kushmanda, Shailaputri, Kaalratri, Brahmacharini, Maha Gauri, Katyayani, Chandraghanta and Siddhidatri. A list of 108 names that is used to describe her is very popularly in use by Hindus and is called Ashtottara Shatanamavali of Goddess Durga. She is known by a variety of names: including Amba, Ambika, Jagadamba, Parvathi, Shakti,Adishakti, Adi Parashakti and Devi. According to Shaktism, Adi Para Shakti—the Goddess, Devi—is the Supreme Being and the believers regard Durga as the root cause of creation, sustenance and annihilation. She is pure energy (referred to as “Shakti” in Sanskrit and Hindu religious context). Being innately formless (known as Adi Parashakti), she manifests herself within the gods and demi-gods so that she may fulfill the tasks of the universe via them. At times of distress, such as when Mahishasura terrorised the universe, she manifests herself in divine form to protect the world. Hence, Durga is also known as Mahishasura Mardini (Bengali: মহিষাসুরমর্দ্দিনী, The Annihilator of Mahishasur).
The historian Ramaprasad Chanda wrote in 1916, the following treatise about the ideological development of Goddess Durga from primitive goddess to her current form: 
“…it is possible to distinguish two different strata – one primitive and the other advanced. The primitive form of Durga (Parvati) is the result of syncretism of a mountain-goddess worshiped by the dwellers of the Himalaya and the Vindhyas, a goddess worshiped by the nomadic Abhira shepherd, a vegetation spirit conceived as female, and a war-goddess. As her votaries advanced in civilization the primitive war-goddess was transformed into the personification of the all-destroying time (Kali), the vegetation spirit into the primordial energy (Adya Sakti) and the saviouress from “samsara” (cycle of rebirths), and gradually brought into line with the Brahmanic mythology and philosophy….”
The Devi Puranas state that Durga is the warrior manifestation of Goddess Adishakti. Durga means the “Invincible One”. Therefore, Goddess Adishakti is the Divine Mother of the Universe who had taken birth on Earth as Parvati to win and woo Shiva. The Lalita Sahasranamam bestows Durga as a name of her indicating that Lalita is none other than a form of Ma Adishakti Parvati.
Durga is the supreme soul, otherwise called Shakti (primordial cosmic energy). As such, she is the original cause of all the present or past worldly occurrences. From Durga, all phenomenon of creation, existence and destruction is generated – through the emergence of two triads of Supreme Powers:
- The masculine Trimurti (Brahma, Vishnu, and Shiva)
- The feminine Tridevi (Saraswati, Lakshmi, and Parvati)
Different terms all referring to the same concept referenced above are – Adhyashakti, Paramatma Shakti or Ati Prakrutika Shakti. Durga is believe to create and control two types of power:
- Natural (Atma Shakti, Prakrutika Shakti, Pancha Mahabhuta Shakti, etc.)
- General (Jada Shakti, Tamashakti)
Durga, as the Mother of the Universe, provides man with the opportunity for salvation and enjoyment of life. Vyasa, the eminent sage and poet of the Devi Bhagavata Purana, has aptly stated “Rudrahinam Vishnuhinam na vadanti janastatha Shaktihinam Yathasarbe probodhanti Naradhamam”. This verse translates loosely as “Powerless persons are despised as mean persons. So, by being devoted to the Supreme, we should be strong and powerful by her grace.”
MAA DURGA is a ferocious form of Devi, the Mother Goddess, the all-powerful almighty goddess. Once the Gods could not defeat the buffalo demon Mahishasur, who was threatening the existence of the universe, the Gods were afraid of this water-buffalo bull because neither Vishnu nor Shiva could prevail against him. They begged lord Shiva for his assistance, and Shiva advised all the Gods to release their shaktis as it was seemed that the joint energy of shakti was only capable of vanquishing Mahishasur. The shaktis of the Gods emerged in female form. Which arose a splendid Goddess with many arms, she was as beautiful as she was lethal and it was the ten-armed who went out to do battle. The Gods called this Goddess DURGA, the invincible one. MAA DURGA was born fully-grown and is depicted as exceptionally beautiful and full of rage.