The Curse of the Ningyo was placed upon the Ningyo race by Ryujin, king of the Orochi. Ryujin, an ally of the Ningyo realized that the Ningyo were immortal. Also knowing that if other sentient races knew that a ningyo's immortality could be attained by eating a ningyo Ryujin cursed the Ningyo. The curse did not harm the Ningyo, however. Rather, any who ate a ningyo's flesh would become immortal, not needing to eat, drink or breathe, but would be cursed for all time. In addition, all Orochi could see invisible markings on these immortals and would not hesitate to take immediate vengeance.