Rudra is a Rigvedic God, associated with wind or storm, and the hunt. The name has been translated as "The Roarer",or "The Howler".

The theonym Shiva originates as an epithet of Rudra, the adjective shiva "kind" being used euphemistically of the god who in the Rigveda also carries the epithet ghora "terrible". Usage of the epithet came to exceed the original theonym and by the post-Vedic period (in the Sanskrit Epics), the name Rudra is taken as a synonym for the god Shiva and the two names are used interchangeably.

There are several suggested etymologies for the theonym rudra. One possible origin is the Sanskrit root rud, or "to cry," which explains reference to Rudra as the "howler." Alternatively, rud has been connected to the verb "to be reddish," which suggest that Rudra's name was inspired by the redness that often characterizes storm clouds. Yet another etymology associates Rudra with the term Rodasi, which refers to "heaven and earth," perhaps implying the god's male and female aspects, which come to fruition in the androgynous Puranic god Ardhanarisvara.

Unlike numerous other Vedic deities, Rudra does not appear to correspond with other members of pantheons that developed out of the Proto-Indo-European tradition. Rather, veneration of Rudra seems to have taken root in pre-Aryan phallus worship. This theory is supported by the discovery of seals at Harappa which bear the image of an ithyphallic deity. This deity has a pair of horns, and is attended on one of the seals by a number of wild animals including a tiger and a rhinoceros. Thus, the erect phallus and close relation to animals suggests that this deity was a prototype of what would become Rudra-Shiva, whose character would be further developed in the Vedas. Further, the deity pictured on these seals is seated in a posture with legs pulled up to the chest and heels touching, which would later become an important aspect of yogic meditation. This has lead some to suggest that Rudra-Shiva's later role as the archetypal yogi may have had a non-Aryan origin.

Mythologically, Rudra also embodies many qualities associated with Varuna, the supreme god of the early Vedas who was eclipsed by Indra. As the Great God of the later Vedas, Rudra inherited many of Varuna's essential attributes. For example, Varuna's power of maya, or his ability to create forms in the physical world, seems to have gradually became Shakti, the creative force which is identified as one of Rudra-Shiva's paramount powers.

Rudra is frequently described as the most terrifying of all divine beings. As the divine archer, he rides upon a chariot, constantly in search of beings to devour. He is armed with arrows that inflict disease upon whomever he hits, whether they be human, animal or even a god. Thus, every single being, divine or mortal, lives in fear of Rudra. Rudra is also notable for his unpredictability. Prescribed courses of actions do not always satisfy him, for he is not easily pleased. Even a minor transgression by one of his most faithful devotees can send him into a tempestuous rage. Rudra's temperament seems to be an anthropomorphic representation of nature's most ruthless forces, such as lightning, wind and forest fires. Apparently, Vedic poets saw Rudra as the cause of these fear-inducing natural phenomena, and therefore connected him with everything terrible. Rudra came to be portrayed even more viciously in later texts as a number of indigenous, non-Aryan gods came to syncretized under his name. In the Brahmanas, for example, he is described variously as a murderer, thief, and cheater, as well as the lord of all robbers (see Atharva Veda 11.2.18 and VS 16.20-21).

On the other hand, Rudra is also portrayed in more favorable terms. In the Rg Veda, he is described as a handsome, youthful and intelligent God with braided hair and ornate vestments. Additionally, he is often referred to as the bringer of the fertilizing rains. This association with fertility was probably carried over from Rudra's precursors in the religion of the Indus Valley Civilization. Not only does he possess immense potential for destruction and disease, but also the power to heal. He is frequently described as the divine physician who possesses thousands of remedies for any known malady, and can heal any illness bestowed upon humans by the other gods. This ability to bestow fecundity and heal wounds while also inflicting them exemplifies Rudra's role as the confluence of many diametric opposites.

Rudra is commonly associated with animals. In the Atharva Veda, for instance, he is given the title pasupati, or "Lord of the cattle." The bull is the animal with which he is most commonly associated, another symbol of both rain and fertility in ancient Indian culture. His jurisdiction spread beyond the bovine, however, as he was said to rule over undomesticated animals, as well. He was commonly depicted with numerous creatures of the wild surrounding him. His affinity with animals is reflective of Rudra's more general removal from society. For instance, he kept his residence in the hinterlands, such as the forest and the mountains. In the Yajurveda, his status as man of the wild supercedes his beauty, which was expounded in the Rg Veda, as he was by this time described as an elderly dwarf, clad in the skins of animals.

The form of Rudra most popularly worshiped was Pasupati. According to R. C. Zaenher, devotees flocked to Rudra in this form, envisioning themselves as the herd of cattle over whom Rudra was the master [1] . Due to his close relation with various forms of life and fertility, Rudra was commonly worshipped in the form of the phallic emblem. This emblem came to supplant his anthropomorphic representation, and is still used today in the worship of Shiva.

Regardless of his popularity, only four hymns in the Rg Veda are actually dedicated to Rudra. The most notable of these hymns is the Shri Rudram. This mantra celebrates the various health giving aspects of Rudra and asks for deliverance from the more terrifying aspects of his character:

O Rudra! Salutations to Your anger! Let that anger go towards our enemies, not towards us! Also let (our) salutations be to Your arrow. And also salutations be to Your bow. Also salutations be to Your two hands which hold the bow and arrow. Let all these be active in destroying enemies, but not in me. (from Taittiriya Samhita 4.5.1).

This hymn, as is common with other hymns to Rudra, seeks to eulogize Rudra in order to pacify his wrath and thereby prevent the reciter from becoming victim to the deity's arrows. Although Rudra has been replaced in contemporary Hinduism by Shiva, this mantra is still chanted by Hindus today.