Lonely Isle is a small island located in the Blue Sea. It is one of the locations of the six barrier stones, and one of the three barrier stones location that are located on surface.
The island is filled with black cross graves.
Role in Wadanohara and the Great Blue Sea
Wadanohara and her familiars go there first to fix the barrier. When going in the cave to fix the moonstone, they find an injured Samekichi and battle him.
- Noir makes a cameo appearance there.