Purple Moon Island

is one of the many small land masses that make up the Land of Water, mentioned in Sasuke Shinden: The Teacher's Star Pupil. In the autumn, plankton breed in the water around the island, causing the water to turn red. When the moon is reflected on these waters, the moon appears purple, giving the island its name. The island's first settlers, upon seeing this phenomenon, came to revere nature and established the Purple Moon Religion in worship of it. The religion's strong isolationist policies have rendered the island little-known outside of the Land of Water.