In Chainsawman, Devils are pure manifestations of human fear. They can represent concrete objects, like "spiders," or abstract concepts like "darkness" or "the future." The more human fear is directed at a concept, the more powerful the Devil associated with it becomes. Conversely, if a great number of humans look favorably on a Devil, its strength will decrease. Devils typically feed on human blood and fear, but some are neutral or even benevolent. These demons may even seek to protect humanity from others of their kind.
Power, the Blood Devil
Other than their violence towards humans, these Devils bear little resemblance to those from Western culture. They more closely resemble Japanese depictions of demons and evil spirits. However, the word used to describe them in the original Japanese text is "akuma," which is used to describe Western devils, rather than "youkai," the word for Eastern evil spirits.