text: Vritra (, , ) is a danava in Hinduism. He serves as the personification of drought, and is an adversary of the king of the devas, Indra. As a danava, he belongs to the race of the asuras. Vritra is also known in the Vedas as Ahi (  ). He appears as a human-like serpent blocking the course of the Rigvedic rivers, and is slain by Indra with his newly-forged vajra.
  Etymology
  Vritra literally means "cover, obstacle", in reference of him holding back the waters. It stems from Proto-Indo-Iranian *wr̥trás, from the Proto-Indo-European root *wer- "to cover, to obstruct". The Indo-Iranian word is also found in Avestan as vərəθraγna (Vedic vṛtraghná), literally "(one who) slays obstacles". Functionally, he is related to Jörmungandr of Norse myth, Typhon of Greek myth, and Veles of Slavic myth.
  Literature
  Vedas
  According to the Rig Veda, Vritra kept the waters of the world captive until he was killed by Indra, who destroyed all the 99 fortresses of Vritra (although the fortresses are sometimes attributed to Sambara) before liberating the imprisoned rivers. The combat began soon after Indra was born, and he consumed a large volume of Soma at Tvashtri's house to empower him before facing Vritra. Tvashtri fashioned the thunderbolt (Vajrayudha) for Indra, and Vishnu, when asked to do so by Indra, made space for the battle by taking the three great strides, for which Vishnu became famous, and was later adapted in his legend of Vamana.