The Mother's Daughters

Before the first guilds, in the time of the first creations, Z'hratian night was entirely dark from sunset to sunrise. It was a cold, cruel time when vampires, undead, fey, and other supernaturals wandered freely, protected by the darkness.
It is said that during that time, the Verdant Mother, goddess of nature, fell deeply in love with one of her followers, a wood elf man. She gave birth to twin daughters, the first demigods in Z'hrat's history. The girls grew until they were seven years old (a significant number in Z'hratian traditional numerology), into two beautiful, but strange, silver-skinned children who shone with bright light. 
A few years later, the village they were living in came under attack by a pair of Red vampires. Every night, the vampires would take their prey and slip unseen back into their mountain caves, until the Verdant Mother ambushed them and destroyed them with her powers of light and fire.
After that moment, the girls made their decision: they would, from then on, sit in the sky every night and watch over the people from afar, out of reach of the vampires. They would grant light to the mortals to better allow them to protect themselves. And, in time, that kindness served to attract other protector spirits that shine and sparkle like tiny drops of light in the endless sea of the night.
It is a testament to their generosity and kindness that Z'hrat's twin moons remain, even following the death of their mother.