Varuna is one of the great gods of the Rigveda, associated first with the all-encompassing sky and then increasingly with the waters, and above all he is the guardian of rta, the cosmic and moral order, the deep principle by which the seasons turn, the rivers run to the sea, and truth and right conduct hold. In the Vedic hymns Varuna is a majestic and somewhat awesome figure, a sovereign who sees all: he is said to know the flight of birds in the sky, the path of ships on the sea and the secret thoughts of men, and to bind wrongdoers with his nooses while releasing those who confess and atone. This ethical dimension makes him unusual among the early gods, less a power of nature than a divine upholder of the truthful order of things, before whom human beings feel guilt and to whom they appeal for forgiveness.
Varuna's standing declined sharply in the transition from Vedic to classical Hinduism, without the dramatic humbling narratives attached to Indra; he simply recedes into a narrower, still-honoured role as one of the eight guardian deities of the directions, presiding over the west, and as lord of the ocean and its creatures. He appears in later Puranic myth chiefly in supporting roles, among them the great churning of the cosmic ocean, the Samudra Manthan, undertaken jointly by gods and demons to win the nectar of immortality, a myth set in Varuna's own watery domain even though he is not the story's central actor, illustrating how thoroughly the sovereign moral authority he once held in the Rigveda had, by the time of the Puranas, given way to Vishnu, Shiva and the great Goddess as the primary focus of devotion.