Scattered verses say that Tvashtri fashioned Indra's heavenly bolt: turned, golden, with a thousand edges in one hymn, iron in Indra's own boast in another. He also gave more force to Indra's strength. With it Indra killed Vritra and let the waters out. Separately, the hymns say that Indra from his birth overcame Tvashtri, carried off the Soma and drank it in Tvashtri's dwelling.
Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer § 1.32.2; Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer § 1.52.7; Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer § 1.61.6; Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer § 1.85.9; Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer § 5.31.4; Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer § 10.48.3; Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer § 3.48.4; Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer § 4.18.3
The Kalakeya Danavas under Vritra harry the gods. Brahma tells them to ask the sage Dadhicha for his bones and make from them a six-sided, roaring weapon called Vajra. Dadhicha gives up his body willingly at his hermitage on the Sarasvati. The gods take the bones to Tvashtri, who, filled with joy, builds the Vajra with great care and hands it to Indra with a blessing.
Adds Dadhichi and Brahma; names the material; Tvashtri is glad to help, though Udyoga 9 of the same epic makes him Vritra's maker.
The Mahabharata, tr. K. M. Ganguli (1883-96), sections read for the Vedic layer § vana.100
Vishnu tells the gods to send the Ashvins to beg Dadhyanch for his body, and says that Vishvakarma will make the thunderbolt from the bones.
The maker is Vishvakarma, since Tvashta is here Vritra's father and Indra's enemy.
Srimad-Bhagavatam (Bhaktivedanta Vedabase) § 6.9.53-54
Sources: Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer; The Mahabharata, tr. K. M. Ganguli (1883-96), sections read for the Vedic layer; Srimad-Bhagavatam (Bhaktivedanta Vedabase)
A dialogue hymn in which the unborn Indra refuses the usual way of birth, is hidden by his mother, deserted by the gods and brought Soma by a falcon.
Indra beheads the three-headed priest Vishvarupa, carries the guilt for a year and divides it among earth, trees and women (and, later, water), each for a boon.
Indra kills Tvashtri's three-headed son; Tvashtri shuts Indra out of his Soma, and from the dregs thrown in the fire raises Vritra with a curse that comes out the wrong way round.
Sent by the gods through Agni, three mortal brothers turn Tvashtri's single cup into four and win a share of Soma.
The Sun's wife cannot bear his splendour.
Trita kills the three-headed son of Tvashtri; evil dreams and guilt are sent off to him; the Brahmana explains why.
Brahma kills the demon Vajranabha with his lotus-weapon.
Gods and demons churn the milk ocean with Mount Mandara on the tortoise's back; poison, treasures, Lakshmi and the nectar emerge, and Vishnu as Mohini keeps the nectar for the gods.