In Hindu mythology, the eight Vasus are attendants of Indra in earlier myths, and of Vishnu in later versions.
The eight Vasus are:
Apa - water
Dhruva - the North Star
Soma - the moon
Dhara - the earth
Anila - wind
Anala - fire
Prabhasa - dawn
Pratyusa - light
The Mahabharata tells the story of how they stole the sage Vashistha's cow, which gave unlimited milk. The sage cursed the Vasus to be reborn as men.
The Vasus were horrified at this curse. They asked the river Ganges, a goddess, to become human, give birth to them, and kill them immediately.
The goddess married King Santanu, on the condition that he never ask her any questions about her actions. He agreed, and then had to keep silent as he watched her drown their newborn sons. As she was about to drown their eighth son, Santanu begged her not to kill the baby, and asked her how she could be so heartless. She gave him the baby and vanished.
This baby was Devavrata, or Bhishma.