Dānu, a Hindu primordial goddess, is the mother of the Danavas.
Etymology
The word Danu described the primeval waters which this deity perhaps embodied. As a word for rain or liquid, dānu is compared to Avestan dānu river, and further to river names like Don, Danube, Dneiper, Dniestr, etc. There is also a Danu river in Nepal. The liquid word is mostly neuter, but appears as feminine in RV 1.54.
Myth
Dānu is called the mother of Vrtra, the demonic serpent slain by Indra in RV 1.32. In later Hinduism, she becomes the daughter of Daksha and the consort of Kasyapa.
Temples
As a Hindu goddess, Dānu has 2 temples in Bali, Indonesia: Pura Ulun Danu Temple on Lake Bratan, Bali and Ulun Danu Batur, near Penelokan.