Vishwaroopa's mother belonged to the Rakshasa clan.

Vishwaroopa used to conduct the rites of many religious sacrifices through which the offerings were sent to gods. Still he had a soft corner for his mothers’ kinsfolk. He felt a desire to send those offerings through sacrifices to demons also. Openly he would invoke the gods by their names one by one and let the offerings made to them. But secretly he would utter the names of demons also invoking them to receive the offerings and get satisfied. But this did not remain a secret for too long. The gods got a suspicion and on investigation truth came out. They reported about the priest's disloyalty to their lord Indra. Devendra got terribly annoyed and without a second thought he chopped off the head of Vishwaroopacharya.

The death of his son at the hands of Indra put the carpenter Twashtru into deep grief. He began to entertain thoughts of taking revenge on Indra. He prayed to ' God to grant him a son who would turn out to be a declared enemy of Indra. His prayer was granted. A son was born to him. The father named the baby as Vritra, He grew to become very strong, terrible-looking and most cruel. Both his father and mother told him again and again in his childhood about his elder brother's tragic death at the hands of Indra. Thus his heart was filled with hatred. He would burn with anger at the very mention of gods.

By the time he became a youth leaving behind his boyhood he had been thoroughly trained in the use of all types of weapons. No god who happened to encounter him was able to escape unhurt. He was a source of great joy end inspiration to the entire community of demons. Their hope of defeating the gods grew stronger. They thought that under the leadership of Vritra, when he became strong and old enough to fight, they could rout out the army of gods once and for all. So they were waiting for an opportune time.

At last the war between gods and demons broke out. Vritra was the chief commander of demons. This made them fight boldly. The gods could not bear their blows. Indra and others were in despair.

They approached Brahma and appealed to him for help. Brahma took them to Mahavishnu. All of them stood speechless before that Great God with their heads bowed down, and tears of sorrow rolling down their cheeks. Mahavishnu, the allmerciful and compassionate, comforted them and asked them the reason for their coming.

Then Indra put forth his appeal:

"0, God of Gods! Don't you who are the primal cause of creation, protection and destruction of this entire universe know our plight? Is there anything that we should tell you? From time to time as you know the relations between demons and ourselves get severed, the bitterness grows worse and we come to grips with each other. Under all such circumstances in the past you incarnated and redressed our grievances by trouncing those demons. All that we suffered then has now been forgotten. This Vritra, the son of Twashtru, is so cruel as to put all the demons of the past to shame. Now under his leadership many demons uniting together are attacking us. In one or two tough battle being beaten up and in despair we have come running to you to seek refuge. Only you have to find out some way of warding off our calamity."

Mahavishnu, bearing the responsibility of protecting the world, consoled Indra saying, "0, ye gods, don't be afraid. Go back to the battlefield and fight again. It is not so easy to kill Vritrasura. Yet there is a way. You know, in the mortal world, there is a sage by name Dadheechi who has his hermitage built on the banks of river Saraswati and who leads a pious life of penance and spirituality. Go to him. With due honor and respect, offer your courtesies to him and appraise him of your distress and implore him for help. His backbone contains weapons potent enough to destroy Vritra. The mantras he has mastered by chanting have also enhanced the power of those weapons. If Dadheechi offers his bone to you, give it to Vishwakarma and get the necessary weapons made out of it. Only with those arms can you kill Vritra and win the battle. But Dadheechi will have to sacrifice his body itself in your interest and donate his backbone. How to win his consent is left to you. Now you may go. You have my blessings."