The story of Goddess Naina Devi is associated with the killing of demon Mahishasura. The famous Naina Devi temple is located in Himachal Pradesh. The Goddess is also known as Mahishapeeth because of its association with the story of Mahishasura.
The powerful demon Mahishasura was bestowed with a boon of immortality by Brahma on condition that he could only be vanquished by a woman. Mahishasura unleashed a reign of terror on the devas who in order to save themselves combined their powers or shakti to create a Devi (Goddess Durga) powerful enough to defeat Mahishasura.
Enamored by the beauty of Devi, Mahishasura wanted to marry her. Devi told him that she would do so if he would first defeat her in battle. In the ensuing battle Devi defeated the army and powerful commanders of Mahishasura. She the defeated Mahishasura and plucked out both his eyes and was hailed by the Devas, Saints and human beings with the cries of ‘Jai Naina.’
Thus the Devi came to be known as Naina Devi.