Cloudy Night is an ancient creeper that lived before Herobrine came. They were named by their looks instead of single words. Her wings allow for nighttime traveling through the air
Many historical tablets and scrolls refference Cloudy Night and a few others. She was said to be a leader among the ancient creepers and lead them to ally with a rival species, the spiders. The bond was fatal, and they lost more than they gained. Cloudy Night broke the alliance, and a fight occured.
When Herobrine arived, it was about 20 years after Cloudy Night had died. No one knows how she died, but many suspect that she was growing too old.