Ninjas (忍者, にんじゃ) were warriors prevalent during the Sengoku period of Japan, specializing in espionage and assassination. Due to their unique set of skills and wide range of weapons, demon slayers are often mistaken for ninjas. Humans are not the only ones who practice the art of the ninja (ninjutsu). Some demons have also mastered this trade, such as Hoshiyomi and his demon ninjas.
- Ninja on Wikipedia