Ryomen Sukuna (literally "Two-Faced Demon" in Japanese) is a character said to have appeared in ancient temples in Hida Prefecture, Japan, during the rule of Emperor Nintoku, between the years 313-399 AD.
Stories about him are conflicting, being seen in stories as a man, as a deity, as a demon or specter, among others. According to Nihon Shokio, Chronicles of Japan, Ryomen Sukuna appeared in Hida Province around the year 377, threatening and plundering the population.