Before One-Hundred thousand years ago, day and night were one. It was morning all the time.
One day the gods got angry with it. So they sent the Avenger to destroy it. The Avenger found this creature and was about to kill it when something stopped him. Maybe it was the beauty of day breaking through night. Maybe it was the brilliant moon shining so bright against the pink glow. But whatever it was, it stopped the Avenger. For a long time he just stared at the creature. Finally, he knew what he had to do to appease the gods and himself.
The Avenger tore the creature in half, allowing them to come together briefly twice a day.