Rahu&Ketu!

According to the writings in Mahabharata, once the Adaitya's&Daitya's, sons of Aditi and Diti by the sage of Kashyapa, were fighting over a pot of Amrita, the nectar of immortality.

Vishnu, who is the God, took the enchanting female form of Mohini and offered to distribute it between them. Smitten by her beauty, both sets of half-brothers accepted the offer.

Distracting the Daitya's with her alluring smile, Mohini poured Amrita down the throats of the Adaitya's. One Daitya got suspicious. He went and sat among Adaitya's. As the Amrita fell into his mouth, the sun and the moon recognized the intruder. They alerted Vishnu, who immediately hurled his discus and severed the Daitya's neck.

The head had become the demon Rahu, who swore to eclipse the sun and moon from time to time. Te body became the demon Ketu, a directionless comet.

Since the Daitya's did not get a drop of Amrita, they became Asuras, which means those who did not drink the divine nectar. The Adaitya's  were known as Suras, those who drank the divine nectar. The Suras were Devas, or Gods of light, illuminated by Amrita.