According to Hindu puranas, sage Kaatyaavana ardently worshipped Goddess Durga. Impressed by him and his incessant devotion, sage Kaatyaavan was granted his wish of becoming a father to a goddess, hence Goddess Parvati too birth as Maa Katyayani at his home. She took this birth to destroy demon Mahishasura.
Maa Katyayani is depicted sitting on a ferocious lion, she is represented with 3 eyes, and 4 hands. Two of her left hands are carrying a lotus, and a sword, her other two right hands are seen in Varada, and Abhaya Mudra.
Upon worshipping Maa Katyayani, he devotees get rid from their sins.