"Narada Muni continued: O best of the Pandavas, your two cousins Sisupala and Dantavakra, the sons of your maternal aunt, were formerly associates of Lord Visnu, but because they were cursed by brahmanas, they fell from Vaikuntha to this material world.
Purport: Sisupala and Dantavakra were not ordinary demons, but were formerly personal associates of Lord Visnu. They apparently fell to this material world, but actually they came to assist the Supreme Personality of Godhead by nourishing His pastimes within this world."
"Vrddhasarma, the King of Karusa, married Kunti's sister Srutadeva, and from her womb Dantavakra was born. Having been cursed by the sages headed by Sanaka, Dantavakra had formerly been born as the son of Diti named Hiranyaksa."
"After the demise of Sisupala, Salva and Paundraka, another foolish demoniac king of the name Dantavakra wanted to kill Krsna in order to avenge the death of his friend Salva. He became so agitated that he personally appeared on the battlefield without the proper arms and ammunition and without even a chariot. His only weapon was his great anger, which was red-hot. He carried only a club in his hand, but he was so powerful that when he moved, everyone felt the earth tremble. When Lord Krsna saw him approaching in a very heroic mood, He immediately got down from His chariot, for it was a rule of military etiquette that fighting should take place only between equals. Knowing that Dantavakra was alone and armed with only a club, Lord Krsna responded similarly and prepared Himself by taking His club in His hand. When Krsna appeared before him, Dantavakra's heroic march was immediately stopped just as the great, furious waves of the ocean are stopped by the beach.
At that time, Dantavakra, who was the King of Karusa, stood up firmly with his club and spoke to Lord Krsna as follows: "It is a great pleasure and fortunate opportunity, Krsna, that we are facing each other eye to eye. My dear Krsna, after all, You are my maternal cousin, and I should not kill You in this way, but unfortunately You have committed a great mistake by killing my friend Salva. Moreover, You are not satisfied by killing my friend, but I know that You want to kill me also. Because of Your determination, I must kill You by tearing You into pieces with my club. Krsna, although You are my relative, You are foolish. You are our greatest enemy, so I must kill You today just as a person removes a boil on his body by a surgical operation. I am always very much obliged to my friends, and I therefore consider myself indebted to my dear friend Salva. I can liquidate my indebtedness to him only by killing You."
As the caretaker of an elephant tries to control the animal by striking it with his trident, so Dantavakra tried to control Krsna simply by speaking strong words. After finishing his vituperation, he struck Krsna on the head with his club and made a roaring sound like a lion. Although struck strongly by the club of Dantavakra, Krsna did not move even an inch, nor did He feel any pain. Taking His Kaumodaki club and moving very skillfully, Krsna struck Dantavakra's chest so fiercely that Dantavakra's heart split in twain. As a result, Dantavakra began to vomit blood, his hair scattered, and he fell to the ground, spreading his hands and legs. Within only a few minutes all that remained of Dantavakra was a dead body on the ground. After the death of Dantavakra, just as at the time of Sisupala's death, in the presence of all persons standing there a small particle of spiritual effulgence came out of the demon's body and very wonderfully merged into the body of Lord Krsna.
Dantavakra had a brother named Viduratha, who became overwhelmed with grief at the death of Dantavakra. Out of grief and anger, Viduratha was breathing very heavily, and just to avenge the death of his brother he also appeared before Lord Krsna with a sword and a shield in his hands. He wanted to kill Krsna immediately. When Lord Krsna understood that Viduratha was looking for the opportunity to strike Him with his sword, He employed His Sudarsana cakra, His disc, which was as sharp as a razor, and without delay He cut off the head of Viduratha, with its helmet and earrings.
In this way, after killing Salva and destroying his wonderful airplane and then killing Dantavakra and Viduratha, Lord Krsna at last entered His city, Dvaraka. It would not have been possible for anyone but Krsna to kill these great heroes, and therefore all the demigods from heaven and the human beings on the surface of the globe were glorifying Him."
Krsna Book, Chapter 78
Bhaktivedanta Book Trust. Excerpted from text and purport of HDG A.C. Bhaktivedanta Swami Srila Prabhupada.