Examples of appearance of onryo prior to the Heian Period include the Hayato burial mound at which it is said the Yamato Government mourned the spirits of the enemy during its conquest of the region.
平安時代以前の怨霊とみられるものとしては、大和政権が征服を進める際に敵方の霊を弔ったという隼人塚がある。