Some of the Asuras are very important, and have been worshiped for thousands of years. The most important of these are Varuna and Mitra. Varuna is the god of the ocean, which in olden times was thought to be flowing under the earth. So, Varuna came to be seen as god of the underworld. In ancient times, water was thought to be where wisdom came from. So Varuna is considered very wise, and he gives his wisdom to those who honor him. Varuna's closest companion is Mitra. Mitra mostly means "friend" in Hinduism, but it originally meant "promise". And so Mitra is the god of friendships and promises. He protects people who honor the truth and punishes those who tell lies. The "Mi-" in "Mitra" means "to tie tightly". Friendship and promises tie people to one another.