In the heavenly realm, Indra, the ruler of the gods, was seated on his throne alongside his wife, Shachi Devi. He was filled with conceit due to the adulation and compliments he received from his subjects and followers. As he sat there, Brihaspati, the preceptor of the gods and even of Indra himself, appeared before the gathering. However, Indra did not stand up to greet him or offer him a place to sit. In fact, he showed Brihaspati no deference whatsoever.
Brihaspati perceived that Indra's ego had inflated with arrogance, so he promptly departed from the heavenly realm. Indra soon realized his fault and searched for his guru to express regret and seek forgiveness. However, despite sending search parties everywhere, Brihaspati could not be located.
Taking advantage of the gods' disrespect towards Brihaspati, their guru, the asuras, who are the gods' eternal enemies, launched an attack on the heavenly realm. Despite their full force, the gods were defeated and badly injured by the asuras. Seeking refuge, the gods turned to Brahma for help, who told them that their defeat was a consequence of their failure to show proper respect to a holy person like Brihaspati. He advised them to seek the help of Vishvarupa, the son of Tvashta, and win his favor with their service and respect. Although he was young, Vishvarupa was their only hope for salvation.
The devas approached Vishvarupa for assistance, and he accepted their request. Through his intense sacrifices, austerities, and meditation, he stripped the asuras of their strength and transferred it to Indra. With their newfound power, the gods easily vanquished the asuras and reclaimed their dominion in heaven.
Vishvarupa performed sacrifices for the devas, but being born of an asura mother, he had an affinity for them as well. Thus, while performing sacrifices for the devas, he would secretly offer some of the offerings to the asuras. When Indra learned of this, he became enraged and decapitated Vishvarupa.
Tvashta, Vishvarupa's father, was filled with grief and swore to avenge his son. He commenced a sacrificial ritual aimed at causing Indra's demise. From the flames of the ritual, a fearsome being emerged, called Vritrasura. Following Tvashta's orders, Vritrasura turned against the devas, who launched all their weapons at the demon. Vritrasura consumed all the weapons and deprived the devas of their powers.
The devas found themselves in a difficult situation and resorted to prayer and hymns to Lord Vishnu. Pleased with their devotion, the Lord appeared before them and offered a solution. He informed them that the only way to defeat Vritrasura was to obtain a vajra, a thunderbolt, made from the bones of a perfectly pure and holy rishi, whose body was strengthened by austerities. The Lord instructed the devas to seek the help of Dadhichi, a rishi who had knowledge of Brahman and ask him for his bones to create the vajra.
The devas approached Dadhichi with their request, but he initially refused. He challenged them by saying that giving away his bones would mean inviting death, which nobody wants. However, the devas responded by praising Dadhichi's compassion, holiness, and selfless service to others. Eventually, Dadhichi realized that he could serve the devas by giving them his bones. He said that while the body is dear to all, it must one day perish, and he would be fortunate if his body could be of service to others. He then went into deep meditation, united with the Supreme Brahman, and left his body on earth.
Indra was given the vajra made from Dadhichi's bones by Vishvakarma, and the devas launched an attack on the asuras. A fierce and terrifying battle took place on the banks of the river Narmada.
The devas, wielding the vajra made from Dadhichi's bones, appeared invincible, and the asuras fled in terror. Vritrasura, seeing his army retreating, shouted, "Indra! You killed my beloved brother Vishvarupa. You will be punished for it today. I am fortunate to have you standing before me so I can avenge my brother's death. However, if you are thinking of destroying me with the vajra made from Dadhichi's bones, it would be a blessing for me. Your divine weapon is strengthened by the austerities of that great sage and is infused with the Lord's power. You have been sent by Lord Vishnu himself, and wherever the Lord is, triumph is certain. If I die today, my worldly bonds will be severed by the grace of Sri Hari, and I will attain his lotus feet."
The battle intensified as Vritrasura hurled his deadly trident at Indra, but the latter skillfully sliced it with his vajra and proceeded to chop off one of Vritra's arms. However, Vritra retaliated by hitting Indra on the cheek with his mace, causing the vajra to slip from his hand and fall to the ground, much to the shock of the devas. Nevertheless, Vritra encouraged Indra to pick up his vajra and continue fighting, stating that victory, defeat, happiness, misery, life, and death were all the same to him as he knew they were mere instruments of the Lord. He added that the three gunas of sattva, rajas, and tamas belonged to Prakriti, and the Atman was just their Witness, and that their battle was akin to a game of dice where the outcome was unpredictable.
Indra was amazed to hear the asura speak with such wisdom, and he responded, "Vritrasura, your words are those of a person who has attained enlightenment through devotion to God. It is amazing to hear that you have surrendered to Lord Hari, who is the true friend of all beings and the inner Self of all. You have undoubtedly surpassed the illusory power of the Lord and have attained immeasurable happiness as a result of your unwavering devotion."
The battle recommenced, and Indra, wielding the vajra, severed Vritrasura's remaining arm. The asura, now armless, opened his massive jaws, as wide as the sky, and lunged at Indra, swallowing him and his mount, Airavata, whole. However, thanks to Vishnu's protection, Indra did not perish; he promptly cut himself free from the asura's belly and decapitated him with the divine vajra. Thus, the great battle ended. All the onlookers saw a radiant effulgence, the light of the Self, emanate from Vritra's slain body and ascend to Vishnu's supreme abode.