Mother goddess cult is deeply entrenched in Indian culture. Small groups and tribes that lay scattered all across India have had their own specific mother goddess worship traditions.
In what is known as the Sangam age (3rd century BCE to 3rd century CE), Kottravai was worshipped as the war goddess in the arid or desert landscapes of ancient Tamilagam (today’s Tamil Nadu).
Similarly, the origins of the war goddess Durga is traced to certain tribes that lived on the the hills of the Vindya mountains (hence, the deity is also referred to as Vindyavasini).
Over time, with the intermingling of the northern and southern cultures, Kottravai gradually began to be identified with Durga-Parvati.
This video discusses the various references to Kottravai that we find in ancient Tamil literature and through these references, traces the metamorphosis of Kottravai into Durga-Parvati.