Demons are natural predators to sapient creatures in Light Scar. They exist in the Hell plane, finding their way to the Natural plane through weak points on the edges of hell or other devils that can create portals. They subsist on the flesh, blood, and fear of intelligent creatures. Though they cannot die, they must serve as underlings to the Major Devils of Hell unless they can rise above their strength and become the new Major Devil.
Each devil represents an aspect of the natural world that is feared. Because of this, they appear in the shape of that fear and have powers relating to it. The majority of devils are Lesser Devils, each representing a specific fear (Fear of swords, lies, saving food for later only to discover it was eaten by someone else the next morning, etc.). The strongest devils the natural world sees are usually Major Devils, which represent an entire category of fear (Fear of weapons, disease, torture, etc.). If a Major devil represents a universally feared subject, they are considered a Primal Devil.