Zorya

In Slavic mythology, the Zorya (alternately: Zarya, Zvezda, Zwezda) are the three (sometimes two) guardian goddesses, known as the Auroras. They guard and watch over the doomsday hound that threatens to eat the constellation Ursa Minor, the 'little bear.' If the chain breaks loose and the constellation is devoured, the universe is said to end. The Auroras represent the Morning Star, Evening Star, and Midnight Star, respectively, although the Midnight Star is sometimes omitted. In some myths, the morning Zorya was the wife of the male Myesyats, the moon god, and was a major goddess. In other myths, the Zoryas are virgin goddesses who flank the sun (see sundog), and Myesyats is an unrelated female moon goddess. The Zorya are associated with marriage, protection, and exorcisms.
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[Other] The Zorya are ancient Slavic sky and light goddesses, honored particularly in Russia. Sometimes only two in number, they are usually portrayed as three, a not uncommon number. They were three Slavic dawn goddesses. There was Utrennyaya, the morning star; Vechernyaya, the evening star; and the midnight Zorya. All have the same job: to guard a chained dog who tries to eat the constellation Ursa Minor, the little bear. If the chain should ever break and the dog should ever get loose, the universe will end. Thus the Zoryas are guardian goddesses.