The story from Markendey Purana
Frightened by the severe penance of Trishira, Indra killed him to protect his authority and power. But the sin of killing a Brahmin took away Indra’s radiance. Trishira was the son of Twashta. Twashta became furious at his son’s death. He plucked one strand of hair from his hair-lock and offered it in the sacrificial fire. This resulted in the creation of a formidable and strong demon named Vritrasur. This demon was created with the objective of killing Indra. Learning about the birth of Vritrasur, Indra sent Saptarishis as emissaries to work out a pact with the demon. The Saptarishis affected the friendship between Indra and Vritrasur. But Indra had other ideas.




