One day a demon named Jwarasur, the demon of fever, started spreading incurable diseases to Katyayani's childhood friends, such as cholera, dysentery, measles, and smallpox. Katyayani cured the diseases of some of her friends. To relieve the world from all fevers and diseases, Katyayani assumed the form of Shitala Devi. With her power, she cured all the children's diseases. Katyayani then requests her friend, Batuk to go out and confront the demon Jwarasur. A battle ensued between the young Batuk and demon Jwarasur. Jwarasur succeeds in defeating Batuk. Then, Batuk, lying dead, magically faded into dust. Jwarasur was shocked that Batuk had disappeared and wondered where he had gone, not realising that Batuk had, in fact, assumed the form of an awful male figure with three eyes and four arms holding a battle-axe, sword, trident and demon head. This figure was pitch-black in colour with flowing locks and eyes ablaze with fury and wore a tiger-skin and a garland of skulls - for Batuk had assumed the appearance of Lord Shiva's ferocious form, the terrible Bhairav. Bhairav reprimands Jwarasur and tells him that he is the servant of Goddess Durga (incarnate as Katyayani). A long discussion ensued but then converted into battle. Jwarasur created many demons from his powers but Bhairav managed to destroy all of them. Finally, Bhairav wrestled with Jwarasur and killed him with his trident. 

Meanwhile, Parvati on the other hand, transformed herself into Sheetala Devi. Sheetala Devi resembles a maiden, she was fair in complexion, wearing light and dark blue robes, wearing a minimal amount of ornaments on her limbs, three-eyed and is looking very youthful in appearance while representing an omnipotent Goddess, as being one among the incarnations of   Durga. In her four hands, she held a bowl, a fan, a small broom, or a winnowing fan she carries a pot of cold water, in which she used to cure the diseased. She was mounted on the back of a donkey as her vehicle. Goddess Sheetala started her mission of providing relief to the children. Wherever Goddess Sheetala went around and over the world, with her most effective tool, her cold and cooling water brought relief to all children, of all shapes, sizes, colors, and ages. They were all completely restored to their good health, which brought instant relief to them and to joy to all the parents. Seeing Goddess Sheetala, everybody paid their homage to her and all the children thanked her for curing their incurable fever and purifying them.