some went as far as to say that the isles were the original abode of the spirits , and thus a place of great enchantment ; but so little was actually known about them , that they next appeared in post-disaster myths , which claimed that the rising of the seventh moon had first caused them to sink , along with their dwellers , then to rise again , lifeless and barren , and ever after to surface and submerge in a pattern no one could ever decipher though never all three at once .