Varuna deva is the deity of water, oceans, and the night sky. He is also the protector (lokapala) of the west direction. He is one of the Adityas, the 12 sons of Kashyapa and Aditi. Varuna is paired with Mitra many times as Mitra-Varuna because of their similar nature. Varuna’s capital city is called Shraddhavati. Varuna is also a member of the congress of Brahma. The Shlok/mantra to invoke Varun deva is ‘Om Vam Varunaya Namaha’.
In Satya Yuga, after Indra killed Vritra, all the devas approached Varuna. “You must become the lord of the waters. You can reside in the ocean. All the rivers and oceans will obey your command. You will wax and wane like Chandra (the Moon),” the devas said. Varuna agreed to their request and Varuna became the god of water.
Varuna is the keeper of the cosmic order, a force called rta. It is rta which keeps everything working as it should, and Varuna’s role as the one who governs rta makes him very important indeed. He is very closely linked to the god Mitra. Varuna is one of the Adityas and considered to be an asura, when those beings were still god-like and had not yet degenerated into demons. He is also associated with the moon and Soma, in Soma’s incarnation as the drink of the gods. Varuna is seen as a white man in golden armour riding a Makara (a sea monster), holding a noose or lasso made from a snake.