Wakan Sansai Zue
Mōryō are considered to be spirits from mountains and rivers, and trees and rocks. They emerge from the life energy of mountains, water, trees, rocks, and all natural things, and fool humans. They are also said to eat the dead, have the appearance of a child, stand on two feet, have dark red skin, have red eyes, long ears, beautiful hair, and a voice that resembles that of a human. With this kind of appearance, they are thought to be oni. In the "Wakan Sansai Zue", they are considered water gods (Suijin), and in the ancient Chinese book Zuo Zhuan, they are considered to be gods of swamps and marshes.