Mutharamman

Once upon a time due to the curse of saint Agathiyar, The saint Varamuni became a man with a buffalow head. The term "Magisam" means buffalow. Since he had a buffalow head he was called Magisasuran. With his continuous meditation and strenuous effort Magisasuran gained more power and dominated all over the world. 

https://www.google.com/search?q=Varamuni

To condemn the domination of the Magisasuran the saints approached the Goddess and informed the hardship done by Magisasuran. Then with the power of Goddess there appears a female baby. The baby was named as Lalithambigai. The baby grown up within 9 days and on the 10th day she grew as Annai Parasakthi Lalithambigai with lots of anger came strongly and destroyed Magisasuran and this day (i.e.,) 10th day is being celebrated as Dusshera. The growth occurred by Annai Parasakthi during the nine days are resumed as Navarathiri.

1. The first three days for Malaimagal, 
2. the second three days as Alaimagal, and 
3. the last three days as Kalaimagal. 

After the Goddess Annai Parasakthi demolished Magisasuran she was called as Magisasura Marthini. At last the Goddess came to this city and settled and showered her blessing to all the devotees.

https://www.google.com/search?q=Mutharamman