A shifter during the Great Forging realized that without the 12 moons of Eberron, shifters and lycanthropes would have trouble surviving in the new world. He decided to use the powers of the Great Forging to make a super moon. However, the shifter did not know a lot about astronomy, so it was only after he completed his super moon that he realized it would only be full once every three months, and it’s light could only reach a small archipelago between Tretton and the New World. As shifters and lycanthropes throughout the world died out, the shifter took a group of them to these islands, where they thrived off the moonlight from the super moon.
Every three months when it became full, they would lash out in unbeatable raids to everything nearby. It was not long before the islands became populated solely by lycanthropes and their shifter kin. Werewolves became less common in the archipelago, and weresharks, wereeels, and other amphibious creatures began to populate the area. The amphibious lycanthropes were able to easily deal with the awkward tides caused by the super moon.
After a while the islands attained a reputation for being a terribly savage place inhabited solely by beastmen. Ships gave the islands a wide berth when sailing between Tretton and the New World. The lycanthropes of the now called “Lunar Wilds” began to worship the super moon. They now call it by many names, one of the more common being “Evinyone.” It is considered a terrible idea to sail when the super moon is full.