There are nine names of Devi Durga –ShailPutri, Brahmacharini, etc; etc and hence known as Nava-Durga. During Navaratri festivals, all the Devis are worshipped in their particular avatars and celebrated all over the world with fanfare. Devi accepts all the names and proves itself in all forms. When you sit in meditation and deep inside, you will realize the different shakties and their mantras.