The elder raised her sister for the coming night, letting her soothing glow wash across the earth and sea in a gaze only the princess could understand. A way to light the troubles for all who moved in the dark. Gave them a path to follow when no lantern could, when no other natural light was possible. Yet she was there, guiding their path, the elder letting her sister’s strength and power give light to the ponies of Equestria and for so many others beyond. For while her sun graced the other side of the world, soon it would be their turn to rest. Soon, it would be their turn to move in the dark. Soon, they would need her sister’s guiding light.

And even as those on the land needed her guiding light, there were others by sea who found comfort in the heavenly bodies. Those across vast miles of sea to other lands entirely. Those who watched, who pondered, who thanked the heavens for the Mare’s glow to keep them company in the blackness. In the terrors of night, the Mare in the Moon offered a comforting embrace. A white, ghostly glow, but one not to fear. One not to turn away from. For her light guided even the blackest blankets of the deep. Her light showered the creatures who swam in it and gave them peace in the dark.

That was the Mare in the Moon. Known not just to the elder princess, but to every life in their own way. Their own story. Their own light.