Krishna kills the demon vatsasur, vyomasur, agasur and free's river yamuna from kala nag.

In this katha sree krishna kill vatsasur, vyomasur,agasur and Free's yamuna from kalanag who poisoned the river, thus removing the poison from yamuna and making it pavitra.

We learnt in the previous narration that falling of the twin trees had sent a current of fear throughout Gokul and people apprehended some fearful calamity. They were sure that the demons would not let them live at peace there. So, they left Gokul and settled at Vrindavan. At Vrindavan, Krishna had sought permission of Nand Baba to accompany the cowboys in order to graze his calves. At Mathura, Kansa was not able to sleep in peace out of Krishna's fear after Trinavart's death. His death looked sure and imminent. So, he sent for another demon to have Krishna killed. This demon could transform himself into any creature. The demon came to Vrindavan in the form of a calf and mingled with Krishna's calves. But Krishna was able to spot the new calf before long. His keen insight guided him on to reality and he alerted his brother Balram against this demon--Vatsasur. Before Vatsasur could do anything, Sri Krishna got near him slowly, caught him by the hind legs and lifting him threw him upwards. After striking against a nearby tree, Vatsasur fell down on the ground with a thud and was killed. The cowboys were so pleased at Krishna's exploit that they began to dance merrily. Vatsasur's murder by Krishna gave a serious shock to Kansa and his death seemed staring him in the face. So, he sent for Pootna's brother and incited him to avenge his sister's death by killing Krishna. Pootna's brother transformed himself into a huge crane and flew to Vrindavan. He was looking for an opportunity to attack Krishna and make short work of him in order to avenge his sister's murder. After a cool thinking, he came to the pool where the cowboys of Vrindavan brought the cattle for a drink. As usual, the cowboys came to the pool with their cattle. But they were highly amazed as well as frightened to see the huge crane. Some of them ran to Krishna and told him about the crane. Krishna at once ran to the pool and saw the crane that had an unusual size. He followed that it was some demon in reality. So, he advanced towards Vatsasur who lifted him in his beak. Krishna made his body so hot that it began to emit flames and so Vatsasur had to open his beak causing Krishna to fall on the ground. Now he began to attack Krishna with his strong pointed beak. But Krishna was more than a match for him was. He caught his beak in his hands and tore it apart. Vatsasur gave nut a loud painful scream and dropped lifeless on the ground.

Hearing of Vastasura's murder, Kansa felt the ground slipping from under his feet. Lost in deep worry, he began to exert even harder for his safety. He contacted Vyomasur, son of Maidanav, the chief of the demons and entrusted to him the task of killing Krishna. Vyomasur assured Kansa of his success and made for Vrindavan. Reaching there, he took stock of the situation carefully. Then he chalked out a plan and transforming himself into a cowboy, joined the company of Krishna's mates. After winning their confidence, he suggested a game to be played. In this game, most of the cowboys were to act as sheep and a few as their guards. As for Vyomasur, he was to act as a thief to steal the sheep away. So, he began to take away the sheep-cowboys and shut them in a cave. Not only this, he carried away some guard-cowboys as well. Thus he was able to shut up most of the cowboys in the cave. When only four or five cowboys were left behind, Krishna became doubtful and he followed the demon stealthily. Seeing him shutting a cowboy in a cave, Krishna saw through his trick and fell upon him. Vyomasur came to his real form and a fierce combat began. Krishna gave him such a terrible blow that he fell down lifeless. Then Krishna set all the cowboys free and they all returned to the pasture.

Hearing of Vastasura's murder, Kansa felt the ground slipping from under his feet. Lost in deep worry, he began to exert even harder for his safety. He contacted Vyomasur, son of Maidanav, the chief of the demons and entrusted to him the task of killing Krishna. Vyomasur assured Kansa of his success and made for Vrindavan. Reaching there, he took stock of the situation carefully. Then he chalked out a plan and transforming himself into a cowboy, joined the company of Krishna's mates. After winning their confidence, he suggested a game to be played. In this game, most of the cowboys were to act as sheep and a few as their guards. As for Vyomasur, he was to act as a thief to steal the sheep away. So, he began to take away the sheep-cowboys and shut them in a cave. Not only this, he carried away some guard-cowboys as well. Thus he was able to shut up most of the cowboys in the cave. When only four or five cowboys were left behind, Krishna became doubtful and he followed the demon stealthily. Seeing him shutting a cowboy in a cave, Krishna saw through his trick and fell upon him. Vyomasur came to his real form and a fierce combat began. Krishna gave him such a terrible blow that he fell down lifeless. Then Krishna set all the cowboys free and they all returned to the pasture.Kansa was now fully alive to the prowess of Krishna but the foolish fellow was not ready to give up his evil ways. He, now, approached Vyomasur's younger brother for help. This demon transformed himself into a huge python and lay on the path along which Krishna and his mates drove their cattle to the pasture. The cowboys, ignorant of the python, kept driving their cattle and were soon inside the wide-open mouth of the huge reptile. They had, in fact, taken it for a crack in a hill. Moreover, they were now fearless, as they were confident of Krishna's indomitable strength. Krishna was coming at the rear. When he saw the wide-open mouth of the python, he called out, "friends! Stop short and turn back. You are advancing into But the cowboys did not hear his call and went on moving the mouth of a python further. So, Krishna ran fast and got into the python's mouth. He began to enlarge his size so that the python might not close its mouth and devour all of them. Krishna enlarged himself so much that the python failed to shut his mouth. On the other hand, he found it difficult to breathe. Thus the python Agasur was choked to death and all the cowboys came out safe and sound along with their cattle.

River Yamuna had a deep pit in it close to its bank where it flowed by Vrindavan. There lived an extremely poisonous cobra along with its family in this pit. This cobra had a hundred and one hoods and the poison that it spat had poisoned that part of the Yamuna. One day the cowboys brought th eir cattle to the Yamuna near that pit. As soon as the cattle drank the water, most of them lay dead then and there. Not only this, some cowboys also met with the same fate. So, Krishna decided to kill the cobra in order to check the water of Yamuna from being poisoned any more. One day, Krishna went near that pit to play with his mates. While playing, he threw the ball into the pit purposely and then to get it,he jumped into the river. Kaliya, as the cobra was popularly called, got furious and hissing violently, it gripped Krishna in its curl and caused him to swoon. The cowboys raised a hue and cry and the entire village of Vrindavan assembled at the shore. Now Krishna began to enlarge his body's girth and the bones of Kaliya's body began to break. Feeling done up, he left Krishna free. Krishna now began to dance on the hoods of the cobra. At the same time, he began to play on his flute. Kaliya's hoods got bruised and he begged to be pardoned. His wives too implored Krishna to pardon their husband. Krishna agreed and the cobra moved to some other place leaving that pit for ever.