In the series, demon ranks are significant as they indicate the strength and abilities of each demon. Demons are ranked from lower moons to upper moons, with lower moons being weaker and upper moons being incredibly powerful. This ranking system helps demon slayers understand the level of threat each demon poses and prepare accordingly.
Demon slayers differentiate between demons and humans through various means, including their appearance, aura, and behavior. Demons often have distinct physical characteristics such as sharp teeth, claws, and unusual eyes. They also emit a different aura or energy compared to humans, which demon slayers are trained to detect. Additionally, demons exhibit predatory and violent behavior that sets them apart from humans. Overall, demon slayers rely on their training and experience to identify and combat demons effectively.