Vrtrasura was the essence of the austerities undergone by Tvasta, yet the thunderbolt killed him. Not only he but also many other stalwart heroes, whose very skin could not be injured even by all kinds of weapons, were killed by the same thunderbolt

Expressions researched:
"Vṛtrāsura was the essence of the austerities undergone by Tvaṣṭā, yet the thunderbolt killed him. Indeed, not only he but also many other stalwart heroes, whose very skin could not be injured even by all kinds of weapons, were killed by the same thunderbolt"

Srimad-Bhagavatam

SB Canto 8

Vṛtrāsura was the essence of the austerities undergone by Tvaṣṭā, yet the thunderbolt killed him. Indeed, not only he but also many other stalwart heroes, whose very skin could not be injured even by all kinds of weapons, were killed by the same thunderbolt.

SB 8.11.35, Translation

Vṛtrāsura was the essence of the austerities undergone by Tvaṣṭā, yet the thunderbolt killed him. Indeed, not only he but also many other stalwart heroes, whose very skin could not be injured even by all kinds of weapons, were killed by the same thunderbolt.