Varuna was one of the most important gods in the early Vedic period. In pre-Vedic times, he was the supreme lord of the cosmos, the keeper of divine order, the bringer of rain, he is responsible for the sun to move in the sky, for day and night to stay separate, and for the earth to keep its form. He is the keeper of the rita and so keeper of Dharma. Varuna is associated with Dyaus.
Dyaus is an Aryan word and is the base for Zeus, Deus and Dieu.

The god Dyaus was already worshipped before the Aryans came to the Indus valley.
Other Aryan tribes brought his cultus to Greece. Dyaus became Zeus.

Dyaus/Varuna was killed by his son Indra. In other stories he is not killed but overthrown by Indra. Varuna/dyaus became less important in time and he became the god of the oceans. Indra and Soma are his sons.

Attributes :

(Trap-) cord (pasha):
That which binds or limits the soul and keeps it (for a time) from manifesting to its full potential. It symbols the ability of the gods to trap evil and ignorance.

Riding Animal :

Makara.
Makara is a sea monster half antelope and half fish.
He symbolizes fertility from water.